Ok. I don't think importing a Windows Library Backup via Restore Library is officially supported in MC Mac.
However, I tested the import and was able to correct the audio paths and then correct the paths in the playlists. Here were the steps required:
1. Make a Library Backup of MC on Windows.
2. Copy that backup zip file to the Mac.
3. Create a new Library on the Mac, and switch to that Library (or use your existing one if you don't care about the content).
Everything else from here on is from the Mac MC
4. Restore the Library from the Backup zip you created on Windows and copied to your Mac. Select Files and Playlists only - don't import Settings.
5. Now you need to change the file paths for your audio files. Select all the Audio files via the Audio > Files view, and use the Rename, Move & Copy tool in Update mode. Change the Base path, and set a Folder rule to mimic and match your existing folder structure. You may need the rules FileFolder(,0) and FileFolder(,1) (or more...) to match your existing folder structure. Unfortunately, Find & Replace is not sufficient to change a drive letter or path components. Play with rules or settings here to get the paths to match.
Your audio files should now be playable in MC (but not via playlists yet).
6. Go to your Audio Playlists. You may want to place them all in a Playlist Group so you can select the Group and make changes to all the entries at once. But first, try just one file within a playlist. You need to make the paths match your new paths on the Mac. This can be done via expression. If you don't know how to do this, show an old path and a new path so that I can help you create such an expression.
Once the path conversion is done, you should now be able to play the files via these playlists.