Okay, I was able to recover some of my data. From the Live CD, I was able to go into the
lost+found folder from the old filesystem. It was full of files and folders that were renamed to meaningless numbers; but, once I went into a folder, everything was named correctly. So by peeking into each one I was able to find the folders containing my data. I created a new 500 GB partition (half of the drive) and named it Data, and moved the 70-ish GB of files I had acquired onto the new partition. Then, I reinstalled linux yet again over the other half of the drive.
I had to fiddle around a bunch with file permission stuff, but I think the partition is now effectively a virtual 500GB hard drive where I can safely store data and still have access to it even after future reinstallations. After getting Firefox set up the way I want yet again, I copied my profile folder onto the Data drive, so next time I can hopefully just copy that back over instead of painstakingly re-setting it up every time.
This should hopefully accomplish two things: one, by having a separate partition for non-system data, I won't be messing with the partition where my OS lives as much, which should hopefully make the filesystem errors less frequent; and two, if my OS does get trashed again, restoring everything should be a simpler and less destructive process.
Calling my local recycling center to see if their facility can accommodate me. Put me in the recycling machine. Turn me into something good. Like one of those fake cans of nuts that you give to an unsuspecting rube, and when they open it, a snake pops out. They can turn me into a snake or turn me into the can. I'm just happy to be part of the team 🦝