Okay, I preliminarily think I've got this figured out. I'm like 95% sure if you disable your TPM in your CMOS/BIOS settings, it'll boot like it's supposed to.
The other 5% chance is that it's now working because I flashed the installer with a different program on Mac OS, instead of with Rufus on Windows as I was before.
I don't currently have the patience to figure out which was definitively the problem.