Skip Lidarr for your initial move. Use Deemix. You can find links to premium ARLs on the wiki or with a google search (or DM me).
Deemix has an option to sign in with your Spotify account and download playlists. There’s a weird song count limit, and you may have to manually hit some tracks. But this is the way.
You can also do Flac with this setup. You don’t necessarily need it, but if you’re making the move, I recommend it. Since Flac is lossless, there’s never going to be an upgrade.