Summary
Toggle first person camera while riding when playing in gamepad mode.



Trivia
I forked ImmersiveHorseRiding to make it work with gamepad and cleaned up the code. That mod and similar mods used to work with gamepads automatically but at some point the game API changed and broke those mods when playing in gamepad mode.


Confession
My solution is kind of a hack, it's not perfect in that you can no longer slowly zoom in and out with by holding down on the D-pad and use the right stick with a gamepad. What you can do now, that you can't on other first person camera mods, is toggle first person mode by hitting D-Pad Down, whether you are mounted or not.

I almost didn't share it but after playing with it a while I find I want to toggle first person much more often than I need to change the zoom amount and when I do want to change zoom amount mouse wheel still works.


Permission
If someone else wants to look at this addon and take the solution I used, you have my permission. FWIW, the author of the mod I forked this from (ImmersiveHorseRiding by Nuojua) also gave permission for someone else to take it over. Basically no one wants to be responsible for maintaining mods I think. I didn't want to either but I really like first person riding and gamepads and nothing was working.

Known Issue
If you were in first person mode when riding, then you dismount, the first time you hit the "toggle first person" button (D-Pad Down) it will appear to not do anything, but if you hit it again it will toggle properly. This is because the game thinks you are already in third person (just with a really close zoom level) and it is putting the camera into actual first person mode. All versions of the first person horse camera addon have always had this issue, I'm just making a note of it.