It’s setup to use GRUB I’m pretty sure. After windows started refusing to boot, GRUB/Ubuntu started yelling about the environment block being too small, although it didn’t prevent Ubuntu from starting up I fixed it anyways by deleting and recreating it (following this), which fixed it.

It’s probably easy to fix, it’s just knowing exactly what happened is probably the most complicated step lol

It really is lol. Doesn’t help that windows error messages are either hyper specific (or more commonly) so vague they’re next to useless with absolutely no in between. Since the error message is hard drive related, all the Microsoft support articles and forum posts are mostly suggesting that the hard drive is completely dead with no hope of recovery and to buy a new one, although since it seems to be working completely fine through Ubuntu I’m doubting that’s the case