Massive FPS drops when selecting a hotkey with many units?

I am getting huge FPS drops from 120 fps down to 10 fps every time I select a hotkey with many units in the mid to late game. It only does it right when its selected and once its selected for a few seconds it goes back up (FPS).

When spamming hotkeys (cycling them quickly) it makes the game a stuttery low FPS mess. This happens on all settings on a decent build (i5 9600k, GTX 1660 TI, 16GB RAM). I tried basically any combination of low graphics settings, turning off sound settings, UI settings etc. Nothing will make this problem go away.

I also talked to several people on Reddit with the issue and 3 of my friends also have it yet whenever I watch a stream they have no issues like this whatsoever. It makes macro really annoying in the late game, and makes micro borderline impossible. Has anyone figured out the cause of this yet?