Microsoft really, really wants you to use a Microsoft Account with your Windows 11 PC.
Microsoft has been pushing hard for its users to sign into Windows with a Microsoft Account. The newest Windows 11 installer removed the easy bypass to the requirement that you make an account or login with your existing account. If you didn't install Windows 11 without a Microsoft Account and now want to stop sending the company your data, you can still switch to a local account after the fact. Microsoft even had instructions on how to do this on its official support website - or at least it used to...
It just doesn't work for my use. I can't keep up with it since my linux machine is used sporadically, and I prefer something more stable. I did like the experience when I tried it though.