I have beaten arbiter of Ash, now what?(3 fragments burning monolith)

So I have beaten the last boss in the game running minion witch Skeletal reavers +support minions for my reavers such as poison+bleed+ignite+shock.

It was fun, but I am not sure what I'm supposed to do now. Just grind the atlas until more content comes out ?

Edit: In steam discussions I was told to level up arbiter skill tree. Is there anything else I need to know ?