Cheers everyone.
As title suggest, today's stable update released by Microsoft for Windows 11 (Pro) made all of my Affinity applications stop working. All I get is error 0xc000135 when I try to open Designer or Photo. When I Google search that code I get that it's NET framework and compatibility related. However, from the 3 updates, installing or uninstalling the NET Framework ones dosen't affect Affinity. It still works as it should. I've narrowed it down to this cumulative KB5013943 update that causes the issue. If I don't install that one, everything works.
The compatibility troubleshooter did nothing useful, to no surprise. I don't know if this is specific to my machine, so someone else please chime in. Meanwhile I'm keeping that update paused from installing.