Hey thanks for the response!
I actually figured this out 2 weeks ago, but due to the inactivity of this thread I figured that this would just get lost in time, so posting a followup wouldn’t be necessary. Since I fixed my problem, I deleted the original screwy installation of eclipse, so I cannot cross-check your suggestions.
That being said, I’ll still try to address your suggestions. I’ve done this enough times to be confident that I did in fact choose the right board, but yes, the build settings were incorrect. Comparing them to a project built when my setup worked, several settings were different, and some completely missing (if I remember correctly, the “Mcu” and “Board” were nonexistent). The reason why I didn’t mention this in my original post was because this was also under the category of things-that-changed-after-doing-something-I-don’t-remember. Since it ended up getting fixed (and I didn’t specifically remember the original settings), I left it out.
As for the compilation flags, I can’t speak to that. I don’t remember at all. I would assume they’d be wrong since the original build settings weren’t correct in the first place.
As for what I did to fix it, I’m actually not completely sure (lol). I just deleted the .eclipse, .p2, and STM32Cube directories, then uninstalled and reinstalled everything. The only notable difference is my java version. I originally used the 13.0.1 jdk, but this time used jdk 8u241. This magically fixed all my problems, including the WinRegistry exceptions. Maybe give that a try?