Windows 11 slowed down many SSDs and HDDs with a faulty implementation of the USN (Update Sequence Number) which is a part of the Filesystem NTFS (a way of saving and retrieving data on the disk).

Micosoft then quickly released a patch that brought some relieve to some users, but left the others still with their slow speed.

This patch KB5008353 should fix the problem that caused the disk slowdown once and for all.
Download it here:  KB5008353

Or get more information on this patch and what other bugs it fixes for you:
Microsoft KB infos