For anyone struggling with DT Hard, I have two words for you
Roric and Vlad. Both free champs from fusions, so you likely have them in your vault.
The two are absolutely stellar for DT Hard. Roric locks enemies down *hard*, while Vlad provides some very valuable TM control as a Void champ, and has a useful A3 to lock down a scary enemy to boot.
(betcha thought I'd say "git gud", eh?)