I have the Corsair M65 Pro , I have 2 of these mice for my system and both are not working. Having the same FPS and mouse not working issue. Just to add, Before this update I had 0 issues with these mice or FPS.
I don't know if this will help anyone but it did in my case, I got tired of waiting for a fix or reply so i was messing around and used VERIFY FILES in the game launcer, The game and mice are working perfect now. Good luck!
if you got a gamepad lying around, connect that one, set it as 1st player control and start the game directly from the installation folder. Playable at least.