MediaMonkey can't Sync from an Apple device to the PC, you'll need to use this procedure: https://www.mediamonkey.com/support/knowledge-base/mediamonkey-sync-iphone-ipod/copy-backup-files-from-an-apple-device/

Did you already do so and don't see the files, then please see: https://www.mediamonkey.com/support/knowledge-base/mediamonkey-database/some-files-dont-scan-into-the-mediamonkey-library/

Trying to aggregate all my music from different - sometimes older tech - sources. I have synched an iPhone 13 and an iPod Classic 160 and only a fraction of the music on these devices appears in the MediaMonkey Entire library