I am kind of shocked about the 7900 xtx. I have the same GPU and I am getting good performance under Linux.

I did some just for fun benchmarking on Doom The Dark Ages last night and I expected Linux to be slightly slower due to the built in ray tracing but I actually got better avgs under Linux. The max frame rate was slightly higher under Windows but the lows were way better under Linux. Overall fairly close performance with a slight edge to Linux.

Maybe Bazzite is doing some magic here. What distro was he using?

Edit: I watched a bit of it, he is running Bazzite, no idea why he is seeing such crazy different numbers. I typically run Proton GE, and I assume he is running Proton Stable, so that would make a dent. People are mentioning low power mode in the comments, but I never have had any issue with that and my 7900 xtx. I haven't had to do anything weird or out of the ordinary.

I think it’s most likely due to me not playing the same games he is, Stalker 2 is basically the only he is playing that I have played in the past and I've haven't done a comparison of that game on Linux vs Windows.