If you truly care about fidelity, vote with your wallet. Move to Tidal or Qobuz. Export your Spotify playlists using free tools like TuneMyMusic and import them into a lossless ecosystem.

Use Spotify for discovery (free tier). When you find a song you love, use (a P2P network for music) or Redacted (private tracker) to find a true CD-ripped FLAC. This is time-consuming but yields the best quality.

Using a Spotify FLAC downloader falls into a legal "grey area."