On Thu, 4 May 2023 at 08:52, Ralf Mardorf <ralf-mardorf@riseup.net> wrote:

to run Windows 11 as Virtualbox guest I build Virtualbox < version 7.

I do not like to say the solution to the problem with program x is to use program y, but if you can at all, I would suggest running an esxi server and running it under vmmware.
vmware is free to use as a standalone esxi server. You can get a free serial just by signing up with an email, which doesn't even have to be your real address.