I logged on and the HUD worked, I tested toggling it on and off using H, but while it turned it off the first time, pressing H again did not turn it back on

Did this issue get resolved?

Did you press any other keys at the same time? Currently by default most hotkeys don't allow any extra keys to be held. Also for example Alt+tabbing in and out of the game can get the Alt key seemingly stuck on, as the game does not see the key release event.

No, I didn't press any other keys, only H, and I didn't alt-tab either. I checked the config in .minecraft and the toggle key is still H. It just doesn't function for some reason, maybe I could try deleting and reinstalling