i haven't had stutters since i've disabled steam overlay
it's worth a shot

didnt work but i didnt think of trying that til now so there's that

forgive me if you've tried this already but have you tried alternating between different dxlevels? do you use steam cloud? it could be keeping certain settings when you reinstall

have you gone as far as trying to play on a fresh windows install? that would 100% tell you if its your hardware or your settings/programs

Do you use an fps config? If so, check if you have mat_queue_mode on 2 then change it to -2. Fixed my stutters back then but it did sacrifice some frames.

Might be your HDD dying

Probably irrelevant but worth a shot, I used to have stutters from an issue regarding the friends list in mainmenuoverride.res
If you want to try make sure the "visible" under the FriendsContainer element are set to "0".

This might sound dumb but i know people this has happen to double check to see if your on 144 hz. Another thing is if your on a mechanical hard drive it could be dying, ive had this happen to me too of them right before they die(games would be real stuttery). Switch to SSD 10x better. If you are on a SSD(they take forever to die), maybe buy another SSD and test it out, if problem persists then obviously return the new one. Its a different issue.

-A little trial and error i guess

*Also if gpu and cpu are newish like you said might be the psu providing unstable amount of power to the components.*

i just fixed this issue for myself by setting cl_smooth to 1 instead of 0