I've owned 2x HomePods, had them hooked up to an AppleTV 4K, and currently own the Sonos Playbar / 2x Sonos One (as surrounds). While the HomePod may sound better to some (and this is always subjective) the Sonos combo in my opinion is the better route if you're looking at home theater.
The HomePods are only going to work for you if ALL of your content is coming from the AppleTV, whereas the Sonos is controlled via HDMI (or optical with an included adapter). The Sonos support AirPlay 2 as well as Spotify if you use that (they show up in the spotify app as devices). The only thing you're "losing" would be Siri, as Sonos supports Google Assistant / Alexa (I don't personally use either one on mine).
As far as the sub goes - my lead has the new Sonos Arc and the PlaySub (I think that's the name?) and he has told me that they keep the sub at like 10% because it is so powerful - just something to keep in mind if you're in an apartment.
I guess my point is this - I loved the sound of my HomePods, but ultimately if I wanted to do anything OTHER than use the AppleTV, they just weren't practical.