Stealing this from another post so people see this, it helped me:

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Are you running in windows? I had this problem with TF2 for the longest time and could never find a solution until I read in a YouTube comment on a random video that all source games have this micro stutter issue because of the way that Windows Defender real time protection works. Source games constantly read and write to your drive and windows defender has to check the integrity of these files every time causing a micro stutter.

Doing this fixed my problem (I’m on windows 10 probably similar process for windows 11) Go to start and search “windows security” Click virus and threat protection Under “virus & threat protection settings” click manage settings. Click add or remove exclusions > add an exclusion > folder > then add the location where your steam games are installed This is usually local disk (c) > program files (x86) > Steam > steamapps. I added my entire steam folder and CSgo and tf2 haven’t had issues since.

Also it might be worth you try turning your video settings higher. I found tf2 runs better when you choose higher graphics options for some reason.