@hilde45 i hope this is at least a little helpful, even though it will not be exactly what you are looking for. I owned the original version of the M33 (now there is a V2), which I believe has the same amplification section as the M23 for about 1 year; i used it with a range of speakers including DALI Epicon 6s and Revel F226Bes. I think the reviews are accurate when it comes to its lack of harshness and its even frequency response. What i can’t entirely tell you is whether its overall sound quality is as dynamic or musical as what i think you would hope for, because I believe the M33 suffers from a pretty mediocre streamer and an only so-so DAC implementation, despite the fancy ESS Sabre chips it uses. For example, when I swapped in a basic Innuos Pulse mini as the streaming input (still using the internal M33 DAC), there was a noticeable improvement in SQ and dynamism (running the Revels at that point). That makes me think that the amp module is OK. I do think it is never going to wow you, however. I think it gives a polite, highly accurate sound, but my hunch is, that, even with a better separate DAC & Streamer, “snappy dynamic speed” is not what it is going to give you. (I sold my M33 to move to a better streamer and separately bought a CODA CSiB V2.)
But, i see that The Audio Factory has a great price on the M23 and i think they have a 60-day return period (you’d pay for return shipping) : B stock M23 So, that’s might make a test in your own room & system attractive?
(I’ve bought a ton of gear from them and always been very happy with the condition of their products and their service. )
Hope this helps, at least a little.