The answer is toolbox or similar container systems. It runs a sandboxed version of another OS inside your Bazzite install with minimal performance overhead. Not quite the same thing as virtualization, but thinking in those terms can be helpful for those new to the concept. It won’t let you run and install everything, but it sure will handle a lot!

As others have said, it might be the new steam recording feature being a touch buggy still. You could also try running the game through gamescope. I’ve had that resolve weird stuttering when game frame pacing wasn’t matching up with the refresh rate of the monitor or compositor properly.

“Collapsing” by Demon Hunter slaps. Thank you, Killing Floor 2, for introducing me.

Epic generally works fine through Heroic launcher. Though I’ve had some occasional problems with Heroic and in those cases Lutris running the Windows Epic Game Store Launcher solved every time. Steam and Proton are still the easiest plug n play though.