First, there is no forced update to Windows 11 from Microsoft's side. I have a laptop that is running Windows 10. I have been nagged to upgrade to Windows 11 a few times, but I have answered "not now" so far.
However, if you are in a corporate environment it may be a different story. Then your IT department may have decided that everyone should move on.
SQL 2012 is not supported on Windows 11. Well, in fact SQL 2012 is not supported at all any more. Nevertheless, I have SQL 2012 running on Windows 11.
But there is a known issue with Windows 11 reporting a disk sector size for certain disk that SQL Server is not able to cope with. Check the SQL Server errorlog. If you see a message towards the end about 256 misaligned reads, this is the issue you are running into. For newer versions of SQL Server, a workaround is to specify trace flag 1800 as a startup parameter. However, I don't think this trace flag is implemented in SQL 2012. Microsoft has published a document with workarounds that you can try. (I have not tried this document myself, as I carefully avoided the disk model for which the problem exists when I built my computer.)