I've been using something Kodi-based for music since the days when you needed to use a doctored James Bond savegame to convince it onto an original XBox. After the XBox became too old to justify, I went through a couple of little black boxes, and I've currently got a
Vero 4K which has been doing all my media stuff for the last couple of years with relatively few complaints.
It's tiny, not too expensive, and for storage I've just got an external USB hard drive which is slowly filling up. Never quite got round to getting an assbox. Or Spotify, for that matter. I can usually convince it to stream stuff from YouTube though, unless the plugin's broken (which happens annoyingly often).
It's connected to the TV, but I've also got it and my record player into a wee mixer, which outputs to my hi-fi in the living room and an old ghetto blaster in the kitchen. I use Yatse remote on my tablet/phone to control it. Multi-room audio for a fraction of the cost of anything Sonos, only downside (if it is a downside) is I'm the only one who knows how it all works (when it works).