Unfortunately Wandering Phoenix (the primary mod) has been MIA for about a year, so you are currently the only active mod now for the Art and Aesthetic communities here.

Either way if you let me know how to make the change I can do it.

On the main page of the Art community, there should be an edit icon toward the top right, just below the community name (looks like a square with a pencil in it). That opens the community edit panel which lets you edit things like the banner, icon, sidebar, and Display Name.

You should be able to change the Display Name to Solarpunk Art, then scroll down until you see the Save and Cancel buttons. Click Save to keep the changed name, and that's it :)