How do I properly use gamescope

I am trying to use gamescope and mangohud at same time so I ran gamescope -e -W 2560 -H 1440 -r 144 --mangoapp %command% (to run at 1440p at 144fps I think) as the launch option on steam but when I load into the game aiming goes crazy like 100x sensitivity but cursor movement (like in setting etc is normal). Is the command wrong...