[SUGGESTION] My solutions

After my old Spotify app died, my 2 main solutions are:

>> https://spotube.es/ - It transfers automatically all your lists from Spotify to its app and it takes the audios from Youtube. You can change the source too. It has synced lyrics for almost all songs, much more than Spotify. You can also download the songs and listen to them offline. It's a bit slow loading sometimes, maybe it's my phone.

>> Youtube Music patched by https://revanced.app/ - You have to download this version https://www.apkmirror.com/apk/google-inc/youtube-music/youtube-music-8-05-51-release/ and patched it with the revanced app. This is my go to music app now.
I already had music playlists on youtube and I transfered my spotify playlists to Youtube Music with https://www.tunemymusic.com . It's free but you have to transfer each list individually and with a 500 song limit. I had a list of 1200 songs and I transferred it in 3 parts. Sometimes it says playlist not found, you just have to retry, and it will work. Don't select 500 songs exactly, select 499.
If you want to transfer official Spotify lists, you can transfer them by first creating a new list on on Spotify on your browser in your PC, then select all songs with Ctrl + A or select first song, then Shift + select last song, then drag them all to your new created playlist.

A friend of mine told me a while ago that he listens to Spotify on his phone with the Firefox browser + Ublock Origin extension. This could be another solution. Good luck.

Edit: Someone in the comments recommended OuterTune instead of Spotube which is buggy. The build of OuterTune looks good. https://github.com/OuterTune/OuterTune . You can enter your Youtube Music account to access your playlists. Only downside for me, you can't store songs in SD card.