I'm on the same situation. My ceiling is concrete with "popcorn" texture, so it's kind of hard for me to do a half decent looking ceiling speaker installation for atmos. I was also looking at shallow white speakers but still not convinced they will look ok. And that is still not even my main concern; which is running wires across the ceiling.
What I've been doing lately is searching for speaker placement alternatives that would put them somewhere high on the wall but not on the ceiling. Problem is my HT area is open at the left to the dining area so that would force me to put a speaker on the ceiling on just one side.
Owm3 or 5 look might be an option. I've seen some others but they get expensive. Have you thought about building a shallow cabinet for in-ceilings? That might be an option.