Hello redjelly39,
Thanks for asking the Apple Support Communities for help with missing playlists.
Is music being removed because your device is out of storage? Check if this feature is enabled and turn if off if you wish: Add music to iPhone and listen offline - Apple Support
- "Free up music storage: If iPhone is low on storage space, you can automatically remove downloaded music that you haven’t played in a while. Go to Settings > Music > Optimize Storage."
If Optimize is not the cause for your music missing, please check these troubleshooting steps next:
1. Try searching for the song or playlist by its name in the Music app and in Search: Use Search on your iPhone, iPad, or iPod touch - Apple Support
If you still can't find your music, follow the next steps based on where the music originated:
2. If you are using Sync Library (Apple Music or iTunes Match):
- Do you have other devices or computers signed in with the same account? If so, is the music or playlists on the other devices?
• Try the following on the iOS device that's missing the music, playlist or content within the playlists:
- Disable Sync Library
- Sign out of your Apple ID
- Restart
- Sign back in
- Enable Sync Library
3. If the music is synced from a computer via USB:
• Can you play the music or playlist available on the computer it was synced with? If so:
- [Playlist] Save a copy of the song or playlist on their computer (select the playlist > File > Library > Export Playlist)
- Connect your iOS device
- Sync over the music or playlist
• If this doesn't resolve the issue, the issue is with music or playlists not properly syncing via USB, please verify everything is followed in this help article: Sync your iPhone, iPad, or iPod using your computer - Apple Support
Thanks and have a wonderful day.