I have Sonos and it is meh. They just issued an apology in the app for how bad their app got, so I can’t really recommend it.
I keep seeing good reviews about Audio Pro. I don’t know too much about them, but they seem to have the same idea of multi-room audio.
Self hosting is the big caveat. There’s a lot of great software options, but the hardware can get to be a bit limiting if you don’t wanna play with common protocols like AirPlay or Chromecast.
Additionally, you could do a Denon or Marantz receiver or Soundbar with multi zone and cover at least 2 spaces wired and add wireless zones via their Heos protocol.
There’s also HomePod, Alexa, or even Bluetooth speakers like the UE Boom or JBL series that you can daisy chain Bluetooth speakers together. No real soundbar solution with this option. Ironically JBL Soundbars don’t communicate with their Bluetoo speakers.
Audio Engine makes some fine speakers that support WiFi or Bluetooth and all they need is power.
Kef has the incredible but pricey LS series of bookshelf and tower speakers. They are independently powered and support all kinds of wireless protocols including AirPlay.
There are a ton of audio solutions nowadays but a lot of them will still require either a wire somewhere or playing with standardized protocols.
I too wish there were a more “self hosted” options. It seems like sooner or later some more viable options will come to light though.