Atmos is object based so, even cheap speakers all around can sound incredible. Especially Atmos Music. I am afraid the olden days of speakers making a big difference, in the case of this technology, matter less. The ROI is less. But more speakers, even small ones, in an Atmos set up can make a difference. During the pandemic, the Atmos mixer with a major label worked at home, in his living room. Which he converted to Atmos using whatever speakers he had laying around! He admitted, they were not pro level speakers but, it pretty much did not matter. I think he still uses the set up to check his work done in a state of the art Atmos editing suite when he gets home.
Having said all that, my set up only has stereo, sub, center, and some repurposed heights on high shelves point direct at me. Mostly because it is a PITA to run the wires for that room. I had hoped to buy some Yamaha MusicCast rears but, the company has stopped making them! But the AVR adapts to the missing speakers automatically and it still sounds incredible! The key is being sure to have the Atmos height speakers. Pointed down from ceiling is ideal and 4, if your AVR can handle that many. I just have two and point them from high shelves. It works!
So the short answer is try anything out you have now. Be sure to read the AVR manual so you know ideal placement and spacing.
