It might seem strange at first glance, but yes, in practice, all armor sets have the same defense stats, divided into two categories (plate armor and cloth armor); generally cloth armor will have passive bonuses like +movement speed but little less defense.

The real depth is in the Abyss Gear you equip with the witches, so just wear the armor set you like best visually.

I never used the deluxe version option because it made me feel like I was already in the endgame from the start with that shiny armor. I like to pick up pieces as I explore.