Playing with controller on Epic Games Store games is annoying, because it's not compatible with Steam's controller support.
Probably understandable, but it means that Steam tries to use "desktop" controls with the controller while I try to play an EGS game, and the inputs won't correspond.
What I have to do is close down Steam, boot up a different controller emulation program, and then I can play on EGS just fine.
Since I play most games on Steam, and use M+KB on most EGS games, it doesn't often come up, it just annoys me when it does.