safari extensions in monterey

After I updated to Monterey 12.2, all my Safari extensions vanished; the preference pane says "no extensions". I had 1password and Grammarly installed before.

I have tried re-activating them from their applications, but I get an error "could not open extension settings. (SFErrorDomain error 1)" from the Grammarly when trying to activate the extension (normally this would open the Safari prefs pane so I can check the extension in the list).

I have talked with 1Password support and followed their advice to restart launchServices. I have tried Safari Tech Preview. I updated to 12.3 this week.

Still nothing. Very frustrating to lost extensions.