Constant failures, especially around update time, sounds like your boot SSD is failing. Try a new one.
Or the NUC board itself has issues. I don’t think these can be easily repaired, so new NUC time.
After replacing hardware, start with a fresh DB (no restore) to confirm that the system is stable, before trying a restore.
This was suggested last time you asked 3 months ago. Did you ever try a new SSD?