Assuming you are looking for Atmos audio output, as one further example, you could use the Sonos Arc for the front Left/Center/Right/Upward-firing audio channels and a separate Sonos Amp for the two rear channels, perhaps using a ceiling speaker pair, that’s if the ceiling speakers are set at an appropriate place in the room.. (I’m personally not a fan of HT front or rear-channel surround audio involving ceiling speakers). I personally prefer those channels to be set at shoulder/head height, when seated, but that’s a matter for your own consideration.
An alternative would be to perhaps use two Sonos One SL’s for the rear surrounds and then utilise a separate Sonos Amp for the 4 ceiling speakers for music audio only, which can of course be ‘grouped’ with the Sonos HT setup for music Playback, but that might likely be overkill for the room, but it maybe worth thinking about, if the ceiling speakers are already in situ and not ideally placed for TV surround audio.
With any Sonos HT setup, you can utilise either one, or two, Sonos Subs as part of the setup, as long as one of the Subs is a gen3 model.
Hope that info. assists.