Controller mode toggle
 

I own a PS4 controller and I used it with DS4Win, that makes it look like an Xbox controller. Now I don't always use it. I intend to use mouse and keyboard most of the time and the controller for combat. Hence I would like a on screen button to turn console mode on/off

Now there is also software named JoyShockMapper that might not be recognized like a controller but as a keyboard. I haven't tested it out, but this might make ESO always in keyb/mouse mode, which is not what I seek.

Gamepad Mode Settings
 

1) Set gamepad mode to "AUTO" and whichever device you're using will be selected for you. No manual switching necessary; or

2) Keybind the gamepad mode toggle.

If you want PS4 or PS5 buttons on screen, there's an addon for that: FCO Gamepad Button Textures.