I would look into Tailscale based on your responses here. I don’t know what your use case is exactly but you set TS up on your server and then again on your phone/laptop and you can connect them through the vpn directly. No extra exposed ports or making a domain or whatnot.
If you want other people to access the server they will need to make a TS account and you can authorize them.
I don’t disagree with you but most of the energy that people complain about AI using is used to train the models, not use them. Once they are trained it is fast to get what you need out of it, but making the next version takes a long time.