> Any suggestions on what I need to upgrade next?

The question of upgrading is honestly as much philosophical in this hobby as anything. You can always chase something else, and different headphones will perform better for certain genres than others, or highlight different aspects of the tracks.

If you really did want something else, you'd have to first state your preferences. Are you currently content with the Deva? Is there anything you feel they are missing? If not, maybe just enjoy them!