I don't find a way to edit these - so i'll update with a reply.
The issue reoccured and i have tested alot of things again - now believe i found the issue - because i can recreate it without fail. (its not the overlays or the polling rate for me, i reenabled those.) The problem on my PC was caused when my USB Gamepad F710 was being plugged in and active during the games!
The controller can be plugged in, but if it was active beforehand, been used by other games beforehand or I pressed a button to bring it to the games attention or it randomly over time came to Paladins attention(i guess), it will then cause massive FPS drops on mouse movement. (noticable ingame by observing the FPS stats (F9) and the game being generally unplayable.) Unplugging the controller has been the quickest and only solution I found, which always solved the issue immediately.
Hope this helps someone. GL with your games.