Some Unreal based games have fps drop when using a 1000Hz polling rate mouse

Compatibility Report

• Killing Floor 2 and Paladins
• 232090 and 444090

System Information

• GPU: NVIDIA GTX 1060
• Driver/LLVM version: NVIDIA 418.43
• Kernel version: Linux 5.0.0-7
• Proton version: 3.16.8 Beta

I confirm:

• that I haven't found an existing compatibility report for this game.
• that I have checked whether there are updates for my system available.

Symptoms

The two following games have a similar issue when the mouse polling rate is 1000Hz (competitive gaming mouses)

Basically any mouse movements cause the FPS to drop consistently from (example) 160 fps to 50

The issue disappears in Paladins when the polling rate of the mouse is set to 500Hz, and in Killing Floor 2 becomes less consistent (even if it is still present a bit)
The only common thing between those two games is the game engine

(The situation is even worse when wine without steam proton is not used, in this case the fps drop to 8 fps when there is a mouse movement causing the game to be unplayable)

This is a similar issue to https://github.com/ValveSoftware/Proton/issues/147 and
https://github.com/ValveSoftware/Proton/issues/1418

But I do not know if they are the same, they are also saying it's fixed in the latest proton version I'm using but I cannot totally say that for me, the fps especially in paladins are still dropping a lot honestly compared when a 1000Hz mouse is used

systeminfo.txt
steam-444090.log

Reproduction

• Have a 1000Hz mouse
• Open one of those two games and play a game

Start by reviewing steam-444090.log and systeminfo.txt, then reproduce the mouse-movement FPS drop in Paladins or Killing Floor 2 with a 1000Hz mouse and compare it with 500Hz. Check the related issues #147 and #1418 for context; done means establishing whether this remains a Proton compatibility problem and documenting a confirmed result.