Take Druid up to 10 for Earth Elemental, followed by Monk 2 and 3 for Unarmored Movement, Flurry of Blows, and a subclass of your choice, for which I recommend Open Hand. Four attacks per turn, two of which might shove your target prone, each dealing 14 damage. And of course you also get all of the standard benefits of an Earth Elemental wildshape like damage resistances and burrowing.

After that is up to you. Keep in mind that you don't need Extra Attack because monsters get Multiattack. Twilight and Peace Cleric are great for all kinds of stuff, but might be hard to justify from a roleplay standpoint. Adding 2d4 to most of your party's rolls is crazy though. Going Monk 4 or Druid 12 for a feat could be nice too.