Recommendations for complete setup for home cinema sound system

[aephir]

I'm looking for what to get for a new home cinema room. I've been doing some research, but would also like some input from someone with more experience.

Especially since a few articles mentioned that I needed to make sure speakers "fit" together. I think the specific quote was to "ensure their timbre were similar enough" (is there a way to do this without actually having access to them, and hearing them together?).

I'm not extremely audiophile, but I appreciate fairly good sound. As a reference point, I am using a NAD275bee with a pair of Dali Zensor 3's for my music, and I'm perfectly fine with the quality in this setup. Honestly, I could probably live with a "quality level" lower for the sound for movies (just to say that anything "higher end" than this would probably be in the "diminishing returns" area for me).

The setup I'm currently considering the most:

• Denon AVR-X2700H
• Tangent Spectrum (2 x X6 (front), 2 x X4 (rear), 1 x XC (center), 1 x XSW-8 (sub). (https://www.whathifi.com/news/tangent-adds-to-its-spectrum-range-to-create-51-system)

However, I don't want upward firing speakers (like Tangent Spectrum XATM). So is there a good fit of in-ceiling speakers that would go well with the above? Preferably something less that 10 cm deep.

Second consideration:

• Denon AVR-X2700H
• Dali Spektor (2 x spektor 6 (front), 2 x spektor 1 (rear), 1 x VOCAL (center), 1 x SUB C-8 D (sub), 2 x Dali Phantom E-50 (height)).

However, there is a ~$560 difference when buying here in Denmark (if assuming height speakers for Tangent is same price as the XATM), and from reviews, I really don't think I'll appreciate any quality difference.

I'm also happy to hear other suggestions.

A few points that might be important:

• The room is 4.0 m x 5.7 m (see sketch below), though only 1.9 m in height.
• The main function is to be connected to the TV (LG OLED C1), so the receiver should preferably support at least:
  • 4k @ 120Hz passthrough
  • Dolby Atmos (need), DTS:X (need). IMAX enhanced would be nice, but not mandatory.
  • eARC (but they all do at this point, right?)
  • HDR10, Dolby Vision, HLG
  • Variable refresh rate (will be used for some gaming)
  • At least a 5.1.2 setup.
• I'll prefer "height" speakers build into the ceiling rather than bouncing sound off the ceiling from upwards firing speakers (there's ~11-12 cm space above ceiling).
• There will be very little room behind the couch (maybe ~30 cm; any implications for rear speakers? They will have virtually no room to "breathe").

Room: