Welcome to the Community and thanks for posting about this!
To confirm, it won't be possible for you to disconnect your Spotify from Facebook if the Spotify account was originally created through Facebook.
To double-check whether that's the case:
- open the desktop app (you can always download it here)
- click the downward arrow next to your username (top right corner) > Settings > Social.
If you don't see the option to Disconnect from Facebook, your Spotify account was created through Facebook.
In that case, you'll need to create a new account by signing up with your email+password and clicking the green 'SIGN UP' button if you don't want your Spotify connected to Facebook.
You can also check this support site article regarding how you can close your present account.
Hope you find this useful. We'll be here in case you need any further help with this 🙂
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