For Windows 11, version 23H2 there is a different regkey you need to set for the "Known Issue Rollback".
On our Windows 11 23H2 clients, the following regkey fixed the issue for now:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Policies\Microsoft\FeatureManagement\Overrides] "1513776270"=dword:00000000
For Windows 11, version 24H2 it does not work. We have not yet found a workaround.
Microsoft told us to rollback to Windows 11, version 23H2 to get rid of the issue :-/