I'm using SDDM for my login, although this issue seems independent of that. I have 2 monitors and I'm setting the resolution before reaching SDDM with xrandr in my /usr/share/sddm/scripts/Xsetup file. However, after I log in, the resolution seems to switch back and forth a bit and cause this very jarring flickering (see video linked below). Is there a way to prevent this? Does plasma run some extra script somewhere along the way to configure the screen resolutions or something that I can modify?

https://i.imgur.com/YilV8N6