Domain forwarding

I’m trying to get back into this as I’ve found a personal use.

I have 2 domains. One is hosted with google domains and the other with namecheap.

I dont really care which one I use as the primary or if I even end up using 2 for my purposes.

I would like to be able to do sub.domain.com and have it hit a IP using a certain port. Google domains will let me do this from 1 domain to another but it shows the hand off. So I go to sub.domain.com and it shows my redirect in the address bar as domain2.com:1234.

I want it to just stay in the address bar as sub.domain.com but hit my IP using the specific port and do a different port for a different sub.

I have an ssl cert rolling on 1 domain and google will make one on the other one easily.

I think I need a SRV record but I cant seem to get it to work.

Any help is appreciated.