Hey @kharjigli , sounds like you are on a mission to better SQ. All of the processors you listed will sound good. I think to choose at a processor below $10K you look at features. If you want 4 subs get the Marantz or the Anthem. The NEW Audyssey software is stunning and extremely flexible. If you get the Marantz I think you will like it. I have a Marantz processor with Audyssey pro and a two channel preamp with ARC. In my room the Audyssey pro works better (my room is well treated, in an untreated room IDK it would be the same). The Marantz offer Auro-3D and DTS-X Pro. That would seal the deal for my personal preference. I find wide channels to be more important then height channels and DTS-X Pro engages them. Atmos not so much depending on the mix. The SDP-58 offers MQA which I happen to like and use a Bluesound Node for. I know the Arcam and JBL previous processors were plagued with bugs, I would definitely want to use a local dealer who makes house calls if I bought those units. I know Anthem is swamped with e-mails (I don’t think they take calls) and it may take 2-4 weeks before they reply to my requests recently. Marantz picks up the phone and is also good with e-mails,. They have been rock solid for service issues. My thoughts would be:
1) Get wide channels and a product that supports them.
2) Make sure the product you purchase is stable, check the forums for customer posts.
3) The new version of Audyssey is superb with the calibrated mic.(paid upgrade)
4) Auro-3D is a plus if you like to upmix music.
My first choice would be the new Marantz unit, my second the Anthem (only because I use Paradigm speakers) and my third the JBL/Arcam because of stability issues with the previous iterations of those units. See my system in profile.