It seems Forza is not mapping my Fanatec CSL Elite PS4 (PC mode) correctly or they don’t work ok in game. I mapped Rewind to the triangle button, then in game I press the button and it does the Rewind, but pressing it again doesn’t work to resume the game from that point as it should, or any other button or the wheel works for that.
I have to connect a gamepad besides the wheel for that, and menus navigation, etc. because the navigation joystick of the wheel doesn’t work either or any button on the menus.
Your experience sounds similar to what I have, in my case a CSL Elite for xBox wheel on xBox 1X. There a few commands that I can only launch from the controller, not the wheel itself. For example, depress the left joystick to vote for the next track - only from the controller, inmpossible from the wheel. Nothing that interferes with driving, but the menus are a whole 'nother story.
I hope there will be better wheel support in this regard from FM 8.
Unfortunately T10 has not allowed for mapping controls outside of driving on the track, (when in rewind the context changes) when you make a custom profile it is possible to have menu binds but only if your wheel has a built in profile in the game, if not the only way to do it is to manually edit the controller config XML to add the context for menu navigation.