It's hard to say since I listen to my NAD m51 with the BHSE + Stax HPs whereas I've only use the NAD m32 with my Sierra-2 speakers. They both sound fantastic though. Going to Germany but will do some comparisons of the two DACs. I bet the NAD m12 is fantastic! Just a little jealous. Would love to have the m12+m22 combo.
I recently bought this grinder but it is for espresso machines (which is the type of machine you should be buying).
Mazzer Mini Doserless Type A grinder
https://clivecoffee.com/product/mazzer-mini-doserless-type-a-espresso-grinder/
I would call these guys up and ask them. Great place.
https://clivecoffee.com/product-category/grinders/
For curiosity sake, I picked up a pair to try out. Not nearly as bad as the DT770 but it still has recessed mids and the bass is a big boomier than I would like. Sending them back obviously. Still really comfy and solidly built.