PS4 controller works in the menu but not the games?

[_Vanillah_]

I just downloaded PPSSPP on my PC so I could play Monster Hunter Freedom Unite, and my controller won't work properly. I can navigate the emulator menus with it, but as soon as I get to the language choice screen of the game it stops working. It works in the save state screen when I press escape, and the controls are set to default.

I tried being in and out of full-screen, getting to the character creation screen with the keyboard, plugging the controller into a different usb port, it just doesn't work.

Any thoughts on how to get it to work?
I'm gonna try other games and see how that goes.