I also happened to purchase a dactyl manuform (4x6+3) from u/brown_elvis lol, same situation as OP in now urgently needing wrist rests. Are you me? lol.
I asked in the mech keeb discord (specifically the #kbergo channel) and got this as a recommendation, mine should be arriving by the 23rd per Amazon, will be able to give my thoughts then. In the meantime, I'm stuck using a regular keeb because I was already getting some wrist pain from neglecting to use wrist rests when I first got my dacman (like an idiot I might add lol)