I learned the hard way about the beauty of backups and the 3, 2, 1 rule. And snapshots are the GOAT.
Even large and (supposedly) sophisticated teams can make this mistake, so dont feel bad. It’s all part of learning and growth. You have learned the lesson in a very real and visceral way - it will stick with you forever.
Example - a very large customer running our product across multiple servers, talking back to a large central (and shared) DB server. DB server shat itself. They called us up to see if we had any logs that could be used to reconstruct our part of their database server, because it turned out they had no backups. Had to say no.
I second the advice to switch to a different/previous/known good kernel. That has been the cause a most boot problems for me. I just had it happen on a VM a couple of weeks ago, so I switched to the old kernel, then removed the new kernel. I’ll wait for another kernel before upgrading.
It’s probably worth scanning your disk just in case as well.