Hope you enjoy your time with the DT770! It’s a great headphone and I’m sure you’ll find many things to love about it…even if it isn’t exactly what you set out to find in the first place! I like the 80 and 250 ohm versions a little more than the 32 for their incredibly soft ear pads, but all three are in my personal top tier.
The Custom One Pros are just a modified DT770 so if they appeal to you, go for them! :) I’ve never owned a pair myself, but the core driver and capsule is 100 percent identical.
From what you’ve said about the Marshalls…they don’t sound great, haha. I try not to review things that people have told me are awful. I self-fund all of my reviews, and I usually end up selling off old pairs to friends, so I’d hate to purposefully buy a clunker! People ask me about Marshall headphones from time to time though, so I’ll add them to my “possible” list….though most dealers near me don’t sell many of their products.
Thanks again for reading!