Multiple failures suggest a hardware issue: Overheating controller, bad backplane, failing PSU…
You’ve lost a file (zpool status -v to know what), but the pool may still be saved.
12 is not that old; I’d try fixing the issue first, upgrading later, and then 13.0U6.2 rather than 13.3 if you have no jails.
If possible, get more drives for replacements and/or making a backup pool.
