RE4 was booting, but not displaying at all for me out of nowhere. I've found out that it's something with Radeon Drivers 21.4.1 or later. If you revert to 21.3.1, it works fine.
Hopefully they fix this in a future update!
Some people on Reddit are saying DXVK fixes it as well, but I couldn't figure that out. Of course, take that with a grain of salt as it's from Reddit.
UPDATE: I've upgraded my drivers to Adrenalin 21.12.1 and RE4 seems to be working fine now. I can get in and play the game. IDK if it crashes down the line somewhere, but this is good news for anyone not wanting basically year old drivers
The boards are now open again and you can now submit your runs with the new LRT.
Remember you cannot use the previous LRT for submissions anymore, so if you haven't already, set up the new LRT through right clicking on your splits → Edit Splits → Search "Resident Evil 4 (Steam)" → Press "Acti