Auto update - now won't load

Catilina auto-restarted on me and tried to update to Big Sur. This has happened before, won't boot, so reinstalled Catalina. However, this time it is stating 'drive is locked' when trying to refresh OS in recovery mode. Is there any way to sort unlock or get files back?

When booting, it get to this and shuts down:

Boot screen before shut off.

Thank you for reading.