UPDATE: I am an idiot.
I was setting the acceleration method for the wrong device all the time. I didn't realize to select the actual mouse from the dropdown in KDE mouse settings until I plugged in my old mouse in.
Anyway that's the acceleration solved. Also as qwesx pointed out, there is some issue with my Logitech Pro X Superlight. The mouse feels more sluggish when using the wireless dongle compared to it being wired. Must be the wrong polling rate or something?