Be Excellent To Each Other

I feel like this is a thread from several years ago, but the upcoming demise of Google Play Music appears to be hitting me hard, so in order to save me signing up for trials of every streaming service ever, I could do with some hive mind guidance.

My requirements are (I thought) fairly simple:
An easy to add to playlist (e.g. GPM thumbs up/Spotify Liked Songs)
Ability to add my own songs where they don't exist, or I have issues with the version that does.
Ability to cast to Google Home (without ignoring my manually added tracks).
Works with Android Auto in the car.

For those of you that haven't seen my ranty YouTube Music thread, my main issues are that casting appears to break everything. YouTube Music only casts 100 tracks from a playlist (unless you jump through hoops), and Spotify won't play tracks not on their servers.

At the moment my best solution appears to be Apple Music, but fuck me, iTunes hasn't got any better since I last used it (I appreciate that in theory I only need to use it to add a few manual songs, but it's so bad).

Please help before I forget to cancel all these trials and bankrupt myself.