I recently manually updated windows to the 2004 version and got some major performance issues. About 1 minute for Firefox, chrome etc to launch! I rolled back to earlier Windows and it was working fine again.
Yesterday Windows updated automatically to 2004 and the problem was back.
Googled and found that it could be caused by a driver from ASUS. I stopped the service called Nahimic Service and the computer was fine.
I just wanted to point this out, that the cause of the problem is the Nahimic driver from Asus! I've no idea how it came into my system but I might have installed some of their crappy software some year ago. (I'm using a ASUS Z390-F motherboard - My next motherboard will probably not be an ASUS product)