Altough this won't work so great for constant syncing, this one-time trick worked for me: I uninstalled the newer version of Spotify, downloaded an older one that imported from iTunes (in my case version 1-0-72-117 from this website: https://spotify.en.uptodown.com/windows/old), successfully imported all playlists from iTunes, and then updated Spotify to the most current version. Done in a matter of a minute or two and no need for 3rd party apps!
thanks a lot! happy to check it out... and sorry if i unintentionally discredited your site. but as a matter of fact bit defender gave out a warning. was more meant to your own info... anyhow, cheers, will check out your software and hope that this can facilitate the issues with spotify!