I have the same problem, see
post https://forums.macrumors.com/thread....2299557/page-104?post=30540552#post-30540552
I'll give it a try. So holding the shift key, get's you into save mode from the EFI boot?
After the system hangs at 40% and you hear the voice over. reboot, hold the shift key when selecting EFI, hold this until it boots into macOS Monterey. Start OpenCore Patcher and select Post-Install Volume Patch. Reboot and your fine.