Is any of the AVR's out there good enough for the NX-Series?
I don't have any experience or recommendation for an AVR. What I can recommend is the Anthem AVM 70 Surround Processor currently retailing for $4000. I use an AVM 60 (the previous model) that I bought new in 2019, after 6 years it works and sounds perfect with zero bugs or glitches.
Anthem AVM 70

The Anthem AVM 60, AVM 70, and the MRX 1140 all use a toroidal transformers, my processor is dead silent. The AVM 60 and AVM 70 are processors only, you have to supply your own amps. I use a Van Alstine Vision SET 400 for the L&R speakers, a Van Alstine 3-channel Insight 240 (120 watts each channel) for the center and surrounds, and a pair of used stereo and 6-channel Adcom amps for the rear and Atmos channels for a system total of 1740 class AB high current watts.
Anthem processors have a smooth, very clear non-fatiguing sound no matter the volume and never, ever a hint of sharpness. The sound quality completely obliterated my old Outlaw 975 processor. The Anthem processor's sound is the opposite of analytical with a sound quality is close to a state-of-the-art movie theater except you get to control the loudness. The center channel volume can be controlled using the remote which is very helpful with bad mixes. If you hear a flaw or distortion it is in the source material and not in the electronics.
The Anthem ARC room correction fine tunes each speaker to sound more alike resulting in an immersive experience without one speaker overpowering the others. I always fine tune the frequency response and loudness after calibration, the software gets the sound close but human ears are the best. The Anthem ARC software is very versatile.

I use the Salk Veracity HT2C center speaker which uses the Seas Excel W18 drivers and RAAL ribbon tweeter in a sealed cabinet, these are the exact same drivers as in my Salk HT2-TL speakers so the tone across the three front speakers is seamless. The Seas and RAAL drivers are also very revealing and don't like harsh or overly analytical sounding electronics at all.
I had two REL subs for a little while: a G2 Gibraltar (far right) and a new G1 MkII. I connected both as an experiment. The sound was visceral but I discovered you can have to much bass. I sold the G2 to a friend and it blends seamlessly with his Magnepan 2.7i speakers.
The TV is a 60" Panasonic plasma, colors look very natural. Black and white films like Roma and 2024's Nosferatu have all the subtle shadings of 35mm film.
