A lot of the material is distributed in 5.1format and no ATMOS.
First of all love the pics you posted and yes, I get it, channel based audio must sound fantastic on both systems. This takes me back to the OP, re: budget. When I bought a $50 Firestick that was 4K/Atmos capable recently with the wifi 6 upgrade I set a $50 expectation. Whoa! The ATV and the Shield are not capable of streaming hirez content, the firestick is. I think amazon loses money on the firestick like kodak lost money on cameras, to get you to buy the film. Martin Logan has atmos speakers on crutchfield you can audition for 60 days, might be worth checking out for the man cave:
https://www.crutchfield.com/S-u8EmbKu42oo/p_839MAFX/MartinLogan-Motion-AFX.html
or The Motion M10 mounted high on the wall near the ceiling:
https://www.crutchfield.com/S-XrWvrG44H9e/p_839MP10GB/MartinLogan-Motion-MP10-Gloss-Black.html