I have Lidarr on Steroids to automate downloads. It uses Deemix to download automatically. Deemix will download in MP3 with a free Deezer subscription, but if you want FLAC you need the premium suscription, or the month trial.
In Lidarr you can import a spotify playlist and it will add all the artists for you, which then downloads through Deemix. You can even download the entire discography if you like. Plus extras like album art.
For streaming I use Airsonic from my PC, then the Substreamer app on my android for the front end. You can create playlists in here and can also download songs on your device for offline play.
When I’m done downloading the majority of my playlists Artists and want to get rid of the Deezer subscription, I’ll probably switch to Usenet and Soulseek to download.
It payed off today, we had a mobile/internet outage for most of the day and I was still able to stream music.