Marantz PM10 class D amp

I wouldn’t be too quick to eliminate options just based on on-paper specs. If that were the case, no one would be buying any tube components. That aside, I’ve only heard two of the components on your list, Marantz PM10 and the ML383 - as well as ML585, but not with KEFs. The PM10 was paired with the Golden Ear Reference and I found the sound hyper-detailed for my taste. Great for the first 10-15 minutes but I felt it lacked musicality. The ML383 was paired with several different speakers including Revel Studio, Harbeth 30.1, and a Paradigm - not sure about the model. It sounded dynamic, musical, and extremely fluid almost regardless of the speakers. The ML585 sounded very similar to the ML383 but it seemed to have a slightly better bass response. If you like the Levinson sound, you’ll not be disappointed with either the ML383 or ML585. You can pick up a used ML585 within your budget.
Good luck.

P.S. I would add T+A elektroakustik HV Series integrated to the list. They seem to get great reviews.

"How can you make statements in regards to amplifier performance/musicality when you are not using the same speakers to compare them (and maybe not even in the same room)?"

You have a fair point in principle but its certainly better than making statements/comparisons just based on on-paper measurements. If you spend the time to go and listen to different component combinations instead of looking at the specs, then your ears will be able to tell the difference. For example, I have heard the GE Reference speakers paired with other amps/preamps like McIntosh and Rogue tube amps and they sounded nowhere as hyper detailed and dry. Some people may prefer that sound.