neowin[.]net/news/your-windows-11-version-21h2-device-will-soon-be-updated-to-22h2-automatically/
windowscentral[.]com/software-apps/windows-11/microsoft-begins-automatically-updating-windows-11-version-21h2-users-to-version-22h2
While the EOL [End Of Life] for the earlier 21H2 isn't until this fall [in October], Microsoft for whatever reason is going to start updating systems automatically -- you'll get a notice to restart to complete the update you didn't know was already half done. Officially they say it's for your improved security, BUT, common sense suggests that it's more work to make sure Windows Updates work on 2 versions of Win11 compared to just one, and Microsoft did just lay off 10 thousand people.
The update isn't *too bad* on rigs that meet Win11's requirements, but I've no idea what happens, if it even works on devices where Win11 was installed using one of the many hacks to get around those requirements.