To @hilde45 its going to be interesting if you proceed with a NAD M23 Class-D amp and compare to other Class A and AB SS and tube amps in your well treated room.
While I’ve not heard one on my system, I do notice if I turn up my full home theater system and watch those higher definition videos with good microphones where they flip back-and-forth between the M23 and Pass Labs amps we both know well, the midrange body and weight of the M23 in the midrange is more bold and forward. No way to trust this, but I have heard this multiple times comparing other amps on these limited video recordings. Not a trustworth test, but it is A vs. B fwiw.
I wonder if that noticeable weight of the midrange and slightly rounded off top end of the M23 is apparent in several real-life listening sessions when paired with your SS and Tube preamps in your treated room. Will be interesting if you try this.

