If you have updated to Windows 11 from Windows 10, the below steps will help you to clean leftovers in your system and make it close enough to the performance known from the 10th edition.
If you planning (or did) to install Windows 11 from an official ISO, make sure that you using always the latest one. At the time of writing this text, the ISO available is the 2nd since the system has been presented to the world (64v1).