Funny you should ask.
I haven't tested it, but after my latest upgrade to Sonoma 15.6, this issue seems to have resolved itself, EXCEPT:
Two VMs I relied on heavily had to be restored from backups. They still raised the same "cannot start VM" error, but I noticed some other macOS VMs had started working.
So something while the system was broken actually broke my favorite VMs with it too, thankfully I had backups and was able to restore them and move forward.
What a mess.