Like I was telling the other guy, it's probably faster to start from scratch on NG than push through an NG+, and probably will be easier on you with the DLC too. But I don't know honestly, somebody who's actually good at the game might have zero issues on NG+ and be better off keeping their levels and stuff.
Having refreshed my memory on the process I should have Mohg dead by tonight. If you are at the start of a new playthrough with an NG+ toon, you can probably be ready to go for the DLC in like 3-4 hours (less if you're actually gud) if that's all you dedicate your time to. It's really not bad. But yeah, how awful the resulting difficulty spike will be is TBD.