I recently went through this decision. Firstly because I was getting saturated with so many services asking for subscriptions, secondly because I'm increasingly seeing songs I like becoming unavailable due to licensing on platforms such as Apple Music and Spotify.
And finally, when I gave YouTube Music a try, I had 500 songs downloaded for offline listening, but had an issue with my carrier in the middle of a work day which left me without an internet connection... And this freaking app didn't let me listen to the songs I already had downloaded. Noped right out of there.
So here's my solution: I created a free trial account on Deezer. I used SongShift to migrate all my songs from my previous streaming apps to a Deezer playlist. I then used deemix-gui to download the entire playlist of off Deezer, at FLAC quality, with lyrics, tags and album art built in.
I now use this library of FLAC files on Music Bee, a free software that looks awesome. When I connect my phone to my PC, Music Bee converts all songs to high bitrate MP3 and syncs with the phone - I then use an open source music player to listen to them.
I get lyrics, high quality audio, albums, artists, playlists... But zero issues with connectivity, streaming, songs losing licenses, subscriptions, and so on.