They are pretty great, but for the EQ, you might want to use autoeq.app and set the profile to Harman Over-ear or their Autoeq profile. The highs on the DT 1990s can be quite aggressive

Are you happy? If yes, then no. Do consider getting a pair of wired headphones or even IEMs based on the recommendations here; you’ll be blown away by the sound quality and clarity they provide for the price when compared to this.

I’d just recommend you get IEMs. You can’t quite get a “real” soundstage with them, but for the price, good IEMs are going to beat closed-backs. Truthear Hexas are some great beginner IEMs