Hello vincewhirlwind,
Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with music not syncing to your watch. Try the steps listed here to see if they resolve the issue: Listen to music and podcasts on your Apple Watch - Apple Support
"How to sync music to your Apple Watch
- Set your Apple Watch on its charger. Make sure that it's charging and that your iPhone is within range of your watch.
- On your iPhone, open the Settings app, then tap Bluetooth. Make sure that Bluetooth is turned on.
- On your iPhone, open the Apple Watch app, then tap the My Watch tab.
- Scroll to Music and tap it.
- Tap Add Music, then find the song or album that you want to sync.
- Tap the Add button next to the music that you want to sync. If you can't add specific albums or playlists, try downloading them to your iPhone before you sync with your watch."
If you're already following this process, and music still cannot be added, Get Support directly from Apple here for more help.
We hope this helps.
Cheers!