Gmod doesn't behave right when I have a second monitor in linux

[elfin sky]

So, I'm running Arch Linux (DE: KDE Plasma) and I have two monitors connected; A 2560x1440 display as my primary and a sideways 1440x900 display as my secondary (it's to the left)
Ever since I hooked up my second monitor Gmod does not behave right. It wants to display on the second monitor and I managed to use special settings in my DE to force it to go on the other one but I cannot get it to use the correct resolution. In the settings it's giving me options from 640x480 up to 1920x1440 and then jumps to 3460x1440 (native). When I apply anything however it just sets it to 3460x1440 anyway. I used a console command to set 2560x1440 and that caused it to go to 640x480 instead.

here's the custom window settings I set

I fixed it

I genuinely have no idea how

but I fixed it

I mean, I wouldn't call it fixed since it's running in 1920x1080 and not 2560x1440 but it's close enough, so now I'm going to just never touch it again

nevermind, it's worse now

ok I figured out what fixed it, I need to do
mat_setvideomode 1920 1080 1
then mat_setvideomode 1920 1080 0
and then not alt-tab or it breaks again

I would not call this fixed

ah, the collision boxes for buttons don't line up with the actual buttons even when this "fix" is applied

This is just wrong

In so many ways

if there's a way to hide a monitor from a program in linux that might work, because gmod behaves as you'd expect whenever this second monitor is disabled, just doesn't behave right with it

maybe that's something I can do with proton?

[crisp vine]

I’ll say as much as a sideways 1440 to a main is certainly unique and probably a result of reusing a monitor you wouldn’t otherwise throwaway.

But uh, good luck

[elfin sky]

The sideways is my secondary

I got it for free, someone left it in the trash room at my apartment

I've had this problem with literally nothing else before now

I went away for a bit and my screensaver triggered, I come back and now the game is behaving exactly how it should

What. The. Fuck.

wait, I know what fixed it

I forgot that I did this

I set it from proton experimental to proton 7

and now everything is better