the causes all sound really random, but one thing that struck me was the fact that the game crashed while changing your sens. Are you on Wayland by any chance? It might be possible that libSDL2 has some issues setting the sens on Wayland, so the game thus crashes. if you are on Wayland, try using this envvar to run TF2's SDL2 stuff in a Xorg server (Xwayland):

SDL_VIDEODRIVER=x11

SDL_VIDEODRIVER=x11

i'm using x11. i've literally tried everything down to removing config commands one by one and nothing has resolved this issue. i'm surprised it isn't more widely being recognized, because it seems more like a hardcoded issue with the game at this point

another update: i decided to play l4d2 for the hell of it, and on linux, i have these awful freezes/fps drops which makes the game almost unplayable. i drop from 300 to what feels like 5 fps every other second.

i'm not sure if this discovery has anything to do with what i've been dealing with in tf2, but it feels like it is. i booted up l4d2 on windows directly afterwards and there are no performance issues at all

if anybody has some answers or pointers i will gladly appreciate it, this whole thing is beginning to drive me mad :(

SDL_VIDEODRIVER=x11

if that's the case I'm going to take another shot in the dark and ask if you're using NVIDIA. might be a driver problem - I have a Radeon and don't have this issue, but it'd make sense if Source games worked well on Windows and poorly on Linux, then

SDL_VIDEODRIVER=x11

yes, i am using nvidia drivers, currently version 525.78.01.
this is my thought too, that the nvidia drivers are causing the problem.
i tried to revert back to a prior version, but i wasn't able to do this without breaking something in the process.
i recorded a video in l4d2 showcasing the stuttering, and i also recorded a video in tf2 where i crashed but it doesn't really show anything that could help diagnose the problem. i don't have any stuttering issues in tf2, it just looks like the video stopped on the last frame (where it crashed) until i ended the recording.
https://youtu.be/2MCvrdn_VY8
if the video is in 360p it's still processing, i just uploaded it

hi, turns out i probably had the same issue yesterday trying to play a lobby, kept crashing, seemed pretty random as to why, happened while i was BATTLING the enemy and happened when i was dead in spec. updated my hud, removed mastercoms and nothing seemed to make a difference, so probably some kind of bug introduced in the last update

good to know, i was beginning to think it was a hardware issue because nobody else was talking about it. have you had issues playing other games too?

That driver version was released just 4 days ago (January 5th) - not quite a week ago, like your original post mentions. If you're memory is just being hazy then it could still possibly be a driver issue. I had a look at that version
's changelog, and there are some Vulkan-related changes, but they don't seem to be anything game-breaking. If you really can't roll-back your driver version and think this is driver-related, then you might have to hang in there and wait for a new, hopefully functioning version to come out

no, tf2 was the only one that kept crashing. no performance issues or any problems with other games

Having the same issue here, also tried everything that you mentioned, rolling back nvidia drivers didn't help, i think it may have something to do with some related packages.

thanks for the heads up! I think the issue might be something related to TF2's low-level graphics, in that case, because of how OP's game instantly crashed after trying to change sens. Might be a good idea to try using different SDL2 versions

Thanks for the recommendation ;), however the issue has been temporarily fixed, here is the link for OP:

https://bbs.archlinux.org/viewtopic.php?id=282586

can confirm that downgrading lib32-libx11 package to 1.8.2-2 stopped crashes.