This is very interesting is this in your own experience or has someone done a nice analysis of this somewhere. I did a quick Google but could only find threads of people complaining about it.

You are right I should’ve used could rather than would. While proton is very good there are very much performance penalties especially for older games due to the adress space nightmare it becomes. I suggested lutris because someone smart probably figured out what the issue is and has created a wine environment that handles it.

I think cs2 has a native Linux build available so that would explain why you get better fps there. Unfortunately I’m not familiar enough with wow to be of much use there. If you launch those games thru steam do they still use the blizzard launcher for authentication? I know some of my friends have had success with lutris for wow so you could try that.