Yeah, AirPlay is such a disappointment. I'm thinking about investing more heavily into Chromecast related things since they're more amenable to custom code. Unfortunately, there's no way I'll sign up for any Google-based music service (and I work for Alphabet!).

Edit to add: Dolby <anything> is also a bit of a fiasco. LG TVs went through multiple firmware updates to attempt to correctly negotiate Dolby Vision. I appreciate that they want to push audio / video quality, but it seems weird that the industry testing process for integration is so poor.