Thank you for the tip. I will bookmark that page in case I need to use that in the future.
I followed the guide “How to restore a Snapper root snapshot on an unbootable system” from FAQ & Tutorials step by step and I was able to reboot the system from the last working snapshot, which I believe was generated just before the update.
There are some visual glitches (mainly Gnome Files and Gnome Settings), but it’s working. I’m gonna backup the few documents I have on that computer to an external drive and try running the updates again. Hopefully, I won’t have the same issue. If I do, maybe it’s time to do a fresh install of the OS using the latest ISO. I hope I won’t have to do that, but I’m mentally prepared for the possibility.