Cause problem is there anyway as a conflict of multiple Installations and / or Windows updates. There is a Solution if you dont have snapshop or backup of vm.

Start VM to recovery mode, select commandline. Remove all xcp related drivers with dism.

https://docs.microsoft.com/de-de/windows-hardware/manufacture/desktop/add-and-remove-drivers-to-an-offline-windows-image?view=windows-11

https://xenbits.xen.org/pvdrivers/win/8.2.2/

(use anytoiso to convert xeniface.tar, xenbus.tar, xenvif.tar, xennet.tar, xenvbd.tar and upload iso-Files to xen iso repository)

Load iso as CD/DVD device with contents of drivers tar files and reinstall the drivers manually by dism.

If you are fast, in 5mins Windows is starting as before.