UI Lagging and Scrolling Left Slower than Scrolling Right

5k 2020 iMac user here. Rendering at 5k makes the UI painfully slow. Granted there is no need to do so but it means hot swapping resolutions whenever using the program. However when I do so it seems to scroll left much slower than it does to the right.

I've seen some other people having similar issues with no results. Is this just a strange 5k monitor problem???

Ta in advance,

-Jamie