Metal Gear Solid 4 -- Can't aim

I've installed the canary patches and have finally gotten the game somewhat stable, using similar settings as to those on the wiki. I'm running a 5800x3d and 4090 and don't seem to have any performance issues, but have run into a very strange issue that I have been unable to rectify: I can't aim any of the guns. L1 does nothing (it does work in menus, so it shouldn't be a controller configuration issue), and R1 simply uses the gun for cqc. I've tested this in the range and had the same behavior.