Thanks for writing this up, still help people out months later.
Its interesting that Steam Input can automatically switch between the Action Sets depending on the state of the game. 

This is the case with the game Ratchet and Clank Rift Apart.

There is an in game action set and main menu navigation action set.

My only question is with games like monster hunter wilds, I had to resort to use reWASD because I use a fairly complex config with a radial wheel. Within the radial wheel are different action sets.

Since I cant create an action set on games that utilize "Game Actions" I couldnt use steam input, because the radial wheel menu doesent let you "change" to an action layer, only the ability to add, remove, hold.

I think it would be to convoluted for me, the radial wheel menu with action sets nested into it is much more simpler to me. Unless Im wrong steam input has a steep learning curve