Are you using Xorg or Wayland? I have only tried Xorg and I found my automatic xorg.conf was a little unusual in that it had two references using the same name. If you have an AMD GPU and a NVidia GPU I am guessing you could see the same thing. 
Failing that, I know I went line by line to get mine to run well. Fine grained power was one of the major buttons for me.
You could also post the configs you’ve tried, someone might spot something…
ps : Sorry, the USB boot was about a possible option to have up your sleeve… Boot an external USB drive with MS Windows on it for games. You do need to be able to disable the internal drive(s) though or, encrypted or not, they will be at risk. It is just an idea, I have several people who now do this, separating work from play.