diff --git a/packages/sanity/src/core/form/store/__tests__/formState.test.ts b/packages/sanity/src/core/form/store/__tests__/formState.test.ts
index d50468172d2..b902457a10c 100644
--- a/packages/sanity/src/core/form/store/__tests__/formState.test.ts
+++ b/packages/sanity/src/core/form/store/__tests__/formState.test.ts
@@ -11,10 +11,6 @@ import {
 import {startsWith, toString} from '@sanity/util/paths'
 
 import {createSchema} from '../../../schema/createSchema'
-import {
-  createCallbackResolver,
-  type RootCallbackResolver,
-} from '../conditional-property/createCallbackResolver'
 import {
   createPrepareFormState,
   type PrepareFormState,
@@ -35,8 +31,8 @@ import {
 import {type StateTree} from '../types/state'
 
 let prepareFormState!: PrepareFormState
-let prepareHiddenState!: RootCallbackResolver<'hidden'>
-let prepareReadOnlyState!: RootCallbackResolver<'readOnly'>
+
+type RemoveFirstChar<S extends string> = S extends `${infer _}${infer R}` ? R : S
 
 beforeEach(() => {
   prepareFormState = createPrepareFormState({
@@ -50,8 +46,6 @@ beforeEach(() => {
       preparePrimitiveInputState: jest.fn,
     },
   })
-  prepareHiddenState = createCallbackResolver({property: 'hidden'})
-  prepareReadOnlyState = createCallbackResolver({property: 'readOnly'})
 })
 const schema = createSchema({
   name: 'default',
@@ -334,7 +328,10 @@ const rootFormNodeOptions: Partial<{
   },
 }
 
-const paths: {path: Path; expectedCalls: {[K in keyof PrepareFormState]: number}}[] = [
+const paths: {
+  path: Path
+  expectedCalls: {[K in RemoveFirstChar<keyof PrepareFormState>]: number}
+}[] = [
   {
     path: ['title'],
     expectedCalls: {
@@ -467,32 +464,35 @@ describe.each(
       expect(startsWith(differentNode.path, path)).toBe(true)
     }
 
-    expect(prepareFormState.prepareArrayOfObjectsInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfObjectsInputState).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfObjectsInputState,
     )
-    expect(prepareFormState.prepareArrayOfObjectsMember).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfObjectsMember).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfObjectsMember,
     )
-    expect(prepareFormState.prepareArrayOfPrimitivesInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfPrimitivesInputState).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfPrimitivesInputState,
     )
-    expect(prepareFormState.prepareArrayOfPrimitivesMember).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfPrimitivesMember).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfPrimitivesMember,
     )
-    expect(prepareFormState.prepareFieldMember).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareFieldMember).toHaveBeenCalledTimes(
       expectedCalls.prepareFieldMember,
     )
-    expect(prepareFormState.prepareObjectInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareObjectInputState).toHaveBeenCalledTimes(
       expectedCalls.prepareObjectInputState,
     )
-    expect(prepareFormState.preparePrimitiveInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._preparePrimitiveInputState).toHaveBeenCalledTimes(
       expectedCalls.preparePrimitiveInputState,
     )
   })
 })
 
 describe('hidden', () => {
-  const pathsToTest: {path: Path; expectedCalls: {[K in keyof PrepareFormState]: number}}[] = [
+  const pathsToTest: {
+    path: Path
+    expectedCalls: {[K in RemoveFirstChar<keyof PrepareFormState>]: number}
+  }[] = [
     {
       path: ['title'],
       expectedCalls: {
@@ -565,32 +565,35 @@ describe('hidden', () => {
     }
 
     // Verify memoization: functions should be called only for affected nodes
-    expect(prepareFormState.prepareArrayOfObjectsInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfObjectsInputState).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfObjectsInputState,
     )
-    expect(prepareFormState.prepareArrayOfObjectsMember).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfObjectsMember).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfObjectsMember,
     )
-    expect(prepareFormState.prepareArrayOfPrimitivesInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfPrimitivesInputState).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfPrimitivesInputState,
     )
-    expect(prepareFormState.prepareArrayOfPrimitivesMember).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfPrimitivesMember).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfPrimitivesMember,
     )
-    expect(prepareFormState.prepareFieldMember).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareFieldMember).toHaveBeenCalledTimes(
       expectedCalls.prepareFieldMember,
     )
-    expect(prepareFormState.prepareObjectInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareObjectInputState).toHaveBeenCalledTimes(
       expectedCalls.prepareObjectInputState,
     )
-    expect(prepareFormState.preparePrimitiveInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._preparePrimitiveInputState).toHaveBeenCalledTimes(
       expectedCalls.preparePrimitiveInputState,
     )
   })
 })
 
 describe('collapsedPaths', () => {
-  const pathsToTest: {path: Path; expectedCalls: {[K in keyof PrepareFormState]: number}}[] = [
+  const pathsToTest: {
+    path: Path
+    expectedCalls: {[K in RemoveFirstChar<keyof PrepareFormState>]: number}
+  }[] = [
     {
       path: ['simpleObject'],
       expectedCalls: {
@@ -657,25 +660,25 @@ describe('collapsedPaths', () => {
     expect(member && 'collapsed' in member && member.collapsed).toBe(true)
 
     // Verify memoization: functions should be called only for affected nodes
-    expect(prepareFormState.prepareArrayOfObjectsInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfObjectsInputState).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfObjectsInputState,
     )
-    expect(prepareFormState.prepareArrayOfObjectsMember).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfObjectsMember).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfObjectsMember,
     )
-    expect(prepareFormState.prepareArrayOfPrimitivesInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfPrimitivesInputState).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfPrimitivesInputState,
     )
-    expect(prepareFormState.prepareArrayOfPrimitivesMember).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareArrayOfPrimitivesMember).toHaveBeenCalledTimes(
       expectedCalls.prepareArrayOfPrimitivesMember,
     )
-    expect(prepareFormState.prepareFieldMember).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareFieldMember).toHaveBeenCalledTimes(
       expectedCalls.prepareFieldMember,
     )
-    expect(prepareFormState.prepareObjectInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._prepareObjectInputState).toHaveBeenCalledTimes(
       expectedCalls.prepareObjectInputState,
     )
-    expect(prepareFormState.preparePrimitiveInputState).toHaveBeenCalledTimes(
+    expect(prepareFormState._preparePrimitiveInputState).toHaveBeenCalledTimes(
       expectedCalls.preparePrimitiveInputState,
     )
   })
@@ -711,13 +714,13 @@ describe('collapsedFieldSets', () => {
     expect(fieldset?.collapsed).toBe(true)
 
     // Verify memoization: functions should be called only for affected nodes
-    expect(prepareFormState.prepareArrayOfObjectsInputState).toHaveBeenCalledTimes(0)
-    expect(prepareFormState.prepareArrayOfObjectsMember).toHaveBeenCalledTimes(0)
-    expect(prepareFormState.prepareArrayOfPrimitivesInputState).toHaveBeenCalledTimes(0)
-    expect(prepareFormState.prepareArrayOfPrimitivesMember).toHaveBeenCalledTimes(0)
-    expect(prepareFormState.prepareFieldMember).toHaveBeenCalledTimes(8)
-    expect(prepareFormState.prepareObjectInputState).toHaveBeenCalledTimes(1)
-    expect(prepareFormState.preparePrimitiveInputState).toHaveBeenCalledTimes(0)
+    expect(prepareFormState._prepareArrayOfObjectsInputState).toHaveBeenCalledTimes(0)
+    expect(prepareFormState._prepareArrayOfObjectsMember).toHaveBeenCalledTimes(0)
+    expect(prepareFormState._prepareArrayOfPrimitivesInputState).toHaveBeenCalledTimes(0)
+    expect(prepareFormState._prepareArrayOfPrimitivesMember).toHaveBeenCalledTimes(0)
+    expect(prepareFormState._prepareFieldMember).toHaveBeenCalledTimes(8)
+    expect(prepareFormState._prepareObjectInputState).toHaveBeenCalledTimes(1)
+    expect(prepareFormState._preparePrimitiveInputState).toHaveBeenCalledTimes(0)
   })
 })
 
@@ -747,12 +750,12 @@ describe('fieldGroupState', () => {
     ])
 
     // Verify memoization: functions should be called only for affected nodes
-    expect(prepareFormState.prepareArrayOfObjectsInputState).toHaveBeenCalledTimes(1)
-    expect(prepareFormState.prepareArrayOfObjectsMember).toHaveBeenCalledTimes(0)
-    expect(prepareFormState.prepareArrayOfPrimitivesInputState).toHaveBeenCalledTimes(1)
-    expect(prepareFormState.prepareArrayOfPrimitivesMember).toHaveBeenCalledTimes(0)
-    expect(prepareFormState.prepareFieldMember).toHaveBeenCalledTimes(8)
-    expect(prepareFormState.prepareObjectInputState).toHaveBeenCalledTimes(3)
-    expect(prepareFormState.preparePrimitiveInputState).toHaveBeenCalledTimes(4)
+    expect(prepareFormState._prepareArrayOfObjectsInputState).toHaveBeenCalledTimes(1)
+    expect(prepareFormState._prepareArrayOfObjectsMember).toHaveBeenCalledTimes(0)
+    expect(prepareFormState._prepareArrayOfPrimitivesInputState).toHaveBeenCalledTimes(1)
+    expect(prepareFormState._prepareArrayOfPrimitivesMember).toHaveBeenCalledTimes(0)
+    expect(prepareFormState._prepareFieldMember).toHaveBeenCalledTimes(8)
+    expect(prepareFormState._prepareObjectInputState).toHaveBeenCalledTimes(3)
+    expect(prepareFormState._preparePrimitiveInputState).toHaveBeenCalledTimes(4)
   })
 })
diff --git a/packages/sanity/src/core/form/store/formState.ts b/packages/sanity/src/core/form/store/formState.ts
index 2bad9c1dc92..0968ab4db91 100644
--- a/packages/sanity/src/core/form/store/formState.ts
+++ b/packages/sanity/src/core/form/store/formState.ts
@@ -222,13 +222,21 @@ export interface RootFormStateOptions {
 
 export interface PrepareFormState {
   (options: RootFormStateOptions): ObjectFormNode | null
-  prepareFieldMember: PrepareFieldMember
-  prepareObjectInputState: PrepareObjectInputState
-  prepareArrayOfPrimitivesInputState: PrepareArrayOfPrimitivesInputState
-  prepareArrayOfObjectsInputState: PrepareArrayOfObjectsInputState
-  prepareArrayOfObjectsMember: PrepareArrayOfObjectsMember
-  prepareArrayOfPrimitivesMember: PrepareArrayOfPrimitivesMember
-  preparePrimitiveInputState: PreparePrimitiveInputState
+
+  /** @internal */
+  _prepareFieldMember: PrepareFieldMember
+  /** @internal */
+  _prepareObjectInputState: PrepareObjectInputState
+  /** @internal */
+  _prepareArrayOfPrimitivesInputState: PrepareArrayOfPrimitivesInputState
+  /** @internal */
+  _prepareArrayOfObjectsInputState: PrepareArrayOfObjectsInputState
+  /** @internal */
+  _prepareArrayOfObjectsMember: PrepareArrayOfObjectsMember
+  /** @internal */
+  _prepareArrayOfPrimitivesMember: PrepareArrayOfPrimitivesMember
+  /** @internal */
+  _preparePrimitiveInputState: PreparePrimitiveInputState
 }
 
 export function createPrepareFormState({
@@ -1247,50 +1255,50 @@ export function createPrepareFormState({
     },
   )
 
-  return Object.assign(
-    function prepareFormState({
+  function prepareFormState({
+    collapsedFieldSets,
+    collapsedPaths,
+    comparisonValue,
+    currentUser,
+    documentValue,
+    fieldGroupState,
+    focusPath,
+    hidden,
+    openPath,
+    presence,
+    readOnly,
+    schemaType,
+    validation,
+    changesOpen,
+  }: RootFormStateOptions): ObjectFormNode | null {
+    return prepareObjectInputState({
       collapsedFieldSets,
       collapsedPaths,
       comparisonValue,
       currentUser,
-      documentValue,
+      value: documentValue,
       fieldGroupState,
       focusPath,
-      hidden,
+      hidden: hidden === false ? EMPTY_OBJECT : hidden,
       openPath,
       presence,
-      readOnly,
+      readOnly: readOnly === false ? EMPTY_OBJECT : readOnly,
       schemaType,
       validation,
       changesOpen,
-    }: RootFormStateOptions): ObjectFormNode | null {
-      return prepareObjectInputState({
-        collapsedFieldSets,
-        collapsedPaths,
-        comparisonValue,
-        currentUser,
-        value: documentValue,
-        fieldGroupState,
-        focusPath,
-        hidden: hidden === false ? EMPTY_OBJECT : hidden,
-        openPath,
-        presence,
-        readOnly: readOnly === false ? EMPTY_OBJECT : readOnly,
-        schemaType,
-        validation,
-        changesOpen,
-        level: 0,
-        path: [],
-      })
-    },
-    {
-      prepareFieldMember,
-      prepareObjectInputState,
-      prepareArrayOfPrimitivesInputState,
-      prepareArrayOfObjectsInputState,
-      prepareArrayOfObjectsMember,
-      prepareArrayOfPrimitivesMember,
-      preparePrimitiveInputState,
-    },
-  )
+      level: 0,
+      path: [],
+    })
+  }
+
+  prepareFormState._prepareFieldMember = prepareFieldMember
+  prepareFormState._prepareFieldMember = prepareFieldMember
+  prepareFormState._prepareObjectInputState = prepareObjectInputState
+  prepareFormState._prepareArrayOfPrimitivesInputState = prepareArrayOfPrimitivesInputState
+  prepareFormState._prepareArrayOfObjectsInputState = prepareArrayOfObjectsInputState
+  prepareFormState._prepareArrayOfObjectsMember = prepareArrayOfObjectsMember
+  prepareFormState._prepareArrayOfPrimitivesMember = prepareArrayOfPrimitivesMember
+  prepareFormState._preparePrimitiveInputState = preparePrimitiveInputState
+
+  return prepareFormState
 }