Have a bug for a new (to me) integrated

I would pick a Luxman, but first I would also spend a few bucks and at least put panels on the first reflection points on the wall and ceiling.

I like Luxman stuff and the room size or room treatments have absolutely zero effect on how an amp sounds. Speakers, on the other hand...

+1 on the Krell k300i.   I have one and it is simply excellent.

From your list, I would lean to Accuphase as well, but I the Krell sounds better to my ears.

@doyle3433 I had the Krell k300i and the Duo 175XD amp which has the same Duo design for both. I loved the sound of both.

It seems to me all your choices are super warm with tubelike characteristics. Other than more power you are not really going away from your comfort zone of tubes.

If you want to really explore the dark side of SS do a 30-day home trial of the Benchmark AHB2 amp with your tube preamp. That could be great and 100% different than all SS amps except maybe the SimAudio Moon 761 + 861 amps.

I just looked up your speakers and see that they are horns. The AHB2 are paired a lot with horns because of the silky-smooth top and deep space like noise level. I once sold AHB2 monos to a guy with horns.

I am debating this myself as I demo an incredible tube DAC vs the most resolving DAC available (SS). What to choose is a tough one.

All the usual suspects, Accuphase, Luxman, Pass each brand excellent in there own unique way. Why not go outside the box, try an older Chord, Esoteric or Plunius integrated. They pop up from time to time in the $4K range. I see an Esoteric I 03 for sale right now on this site. There are Plinius Hauntonga integrateds outing the wild too as well as various Chord pieces. I had a Chord CPM 3300 for a long while and it was an outstanding piece of electronics.
Just my experience