I have a fighting conch and a bunch of burying snails like nassarius. Plus a bunch of other snails, small hermit crabs, an urchin, and an army of mini brittle stars. They are all interesting and do their respective jobs of keeping things under control, but don’t make everything sparkly white. If you added enough to make everything all perfectly clean then they would start starving down to the point where it wasn’t perfectly clean anymore.
From seeing the photos you’ve been posting, my guess is a CUC will not meet your needs alone. You likely will be manually cleaning also.