You want DMZ. I have the same setup. DMZ will make router 1 consider router 2 to be WAN and not behind firewall.

Agreed. All the listed problems seem moot when viewing the project as a personal one.

And people say AI has no use. /s

I did some bad formatting during my initial setup of caddy. Having the formater is really handy.

Depends on the game and your hardware. Most games runs just fine under proton. Valve have done a great job there.

Hardware has never been an issue for me but I read here somewhere that they had 10-15% less performance on Linux. ymmw.