Go for any if the Yamaha/ denons they have plenty of power to drive your speakers even the entry level once. You can upgrade later if you yet have the itch for it
None of the streaming services offer anything beyond 5.1 in DD even for the 4k content. There is just no content beyond DD not even DD+ or true HD no DTS.
Streaming 4k hdr content requires upwards of 30mbps line which is yet rare in India.
Except Netflix noone offers 4k. I have written to hotstar and amazon prime asking when do they intend to start their 4k services and usually i get the answer "we dont know/not so soon".
Hifi customers are niche and in India to have a broadband upwards of 30mbps well it will be some time.
I know so many of my friends who have a 7.2 or even 8.2 but are using it as 5.1 as content is just not available yet even on bluerays.
Speaking of a bluray player would suggest to just skip it for now. I skipped it for the following reasons
1. Content is scares
2. 4k uhd Blu-rays are actually upscaled from 2k take any of the movies all are captured in 2k and not 4k. Eg. Instasteller, Ant man, infinity wars.
3. There isnt much differece in picture quality for the 98% available content.
4. Bluerays are just daam expensive 2.5k for a movie is way too much money.
5. A good 1080p 45-50fps hdr movie will look the same or even better at times on tv as to a 4k as your tv will anyways upscale and display it in 4k.
I have a bluray rip 1080p of Minnions which looks daam good than some of the 4k content.
Ps.
I know i am going off topic but if anyone can share fron where can we get blueray rips would be great as torrents are almost gone now.