iMac 12.1 (21.5”) with OCLP to Ventura hangs on migration assistant?

I managed to get Ventura installed on my mid 2011 iMac and seems to run OK but I cannot use migration assistant.
iMac has 12gb and a Samsung SSD.

It just hangs on the MA setting up screen. I left it for three hours and still nothing. I then have to force quit as the buttons are greyed out.

Any ideas?

Or should I try Monterey instead?