Tool for Spotify download

I just got a synology NAS and want to host my own music instead of relying on a streaming service. What would be the best application for spotify download? spotdl, zspotify-master, something else? I also want the playlists, but then the problem is; I have the same songs in multiple playlists. Is it possible to download all playlists with all songs without duplicating song downloads somehow? Or should i just download the songs and configure the playlists all over again inside Plex afterwards?

TL;DR: I want to download my spotify playlists without downloading the same songs multiple times in different playlists

Thanks for any help in advance