Bug 484568

SUMMARY
The first time Steam is run during an uptime, any mouse cursor movement will become sluggish for over a minute, and window movements will also.

STEPS TO REPRODUCE
1. Run Steam (runtime)
2. Move cursor

OBSERVED RESULT
Mouse cursor will move erratically, sluggishly, and stutterly when you go to move it during the minute or so after the Steam client is loaded. It'll even "teleport" in vectors off from the direction you're trying to move it, making any circle you're moving it in, for example, absolutely fail to complete. It does not matter what window for that time period; it'll even do it over the desktop. Also, moving any windows, maximizing them, or snapping to maximize them becomes significantly sluggish in animation. Intentionally moving the mouse slowly to get somewhere results in less stutters/"teleports", but is not foolproof. 

EXPECTED RESULT
Smooth movement like any other time.

SOFTWARE/OS VERSIONS
Linux: EndeavourOS
KDE Plasma Version: 6.0.2
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2
Kernel Version: 6.6.22-1-lts (64-bit)
Graphics Platform: X11

ADDITIONAL INFORMATION
The reasoning I have to believe it's a bug related to Kwin is that, first of all, the CPU and GPU usage during the bug does not go up noticeably compared to before the bug started happening, second of all, the bug only started happening after one of the updates, and third of all, because it doesn't effect every process and only seems to effect cursor movement and window movement/animation/manipulation.

I'm not sure if it matters, but considering how Nvidia has been in the past: I am using an RTX 3090 Ti
Also, I have one 165Hz monitor as my primary on DP1.4 and 144Hz as secondary on HDMI2.1, both 1440p LG Ultragear.