It was the switch to Microsoft accounts. Everyone started using online accounts to login and when people complained apple said “okay, you don’t need to and here’s some ways to make it safer” after some high profile leaks, google said “we’ll anonymize your data so when we use it for tracking it’s not tied to you, also here’s some ways to make it safer” after everyone realized they weren’t not being evil and Microsoft said “are you fucking stupid? It says right there in the tos that we’re gonna take and use everything!”.
Go to massgrave.dev and start reading. Convert your Microsoft account to a local user account. You will still have a Microsoft account but you won’t use it to login. You will lose access to stuff you bought under your Microsoft account until you sign in. This may or may not be acceptable to you.
Use your knowledge from massgrave to convert your windows edition to enterprise iot ltsc if you’re on 21h2, otherwise either downgrade or flatten and reinstall that edition. You will now be able to receive security updates and stay on windows 10.