Hello @sinatosk, generally speaking, a video driver's on-disk shader cache is a driver-specific detail. There shouldn't be a mechanism in Steam that forces one video driver to use a shader cache of another video driver.
It sounds like the video driver issue you've encountered might be influenced by manually removing or otherwise invalidating mesa's on-disk shader cache. That's a detail to ask your video driver vendor about, and not a Steam client issue.
proton 5.13-6x1 2021-03
Your system information
Please describe your issue in as much detail as possible:
mesa radv has a commit which is causing shaders to be incorrect which in turn is causing DOTA 2 to not start. I later installed Doom Eternal using proton 5.13-6 within steam using mesa radv and sometimes it would start and sometimes not, then I installed amdvlk and the shaders were recompiled and configured Doom Eternal to use amdvlk and it worked. I tried DOTA 2 ( still using mesa radv ) and it worked. I uninstalled amdvlk and shaders were recompiled and DOTA 2 no longer worked and Doom Eternal ( reconfigured to use mesa radv again ) didn't start like DOTA 2.
The shader issue is a bug with mesa radv and I've reported that but I was wondering if it was intentional for amdvlk compiled shaders to be executing on mesa radv?