Well, I've found the answer and it's incredibly cursed: migrating the Oculus account to a Meta account got it into a weird inbetween state where it was simultaneously a developer account but also not.
So half of the device thought it was in developer mode, but the other half (the part that adb interacts with) thought it wasn't, so it didn't show up...
After re-enabling developer mode on the account side, it works again. I fucking hate tech companies so much.