Hello Joulinz81
The best method is to create a bootable USB stick with Windows 11 on another computer. Microsoft offers the Mediacreation Tool for this purpose.
Then boot the PC from this USB, completely erase the hard drive and reinstall Windows. This is the only way to ensure a clean installation.
Gruss TomatoTec
The answer may lie at the end of this link https://steamcommunity.com/app/…
Basically your game activates peer to peer after installation and you become a server for distributing updates.
Check the settings to see if you can disable this function.
DanielD