In my setup, where I’ve simply replicated the built-in FPC blueprint:
“Controller rotation pitch” is checked off, “controller rotation yaw” is checked on, “controller rotation roll” is checked off. This seems to work fine for a standard FPC blueprint.
All of these settings are found under “Pawn” in the details panel under self. I’ve fiddled with them and they don’t seem to change anything.
Also: I’m using Unreal 4.20.3