UDP / TCP Port Forwarding

Hello,

i want to forward ports which are used for udp and some for tcp. May i am missing something but it seems like i cannot change the protokoll from tcp to udp. Ki4a always forwards with tcp. Is this a missing feature? BTW i'm using iptables instead of stock vpn, since i am using Pie which does not work flawlessly with ki4a)

Greetings,
NoDiskNoFun