Hello Jbrisc,
Thank you for using Apple Support Communities! I understand from the information you provided that your Apple Watch is missing some caleners that appear on your iPhone; I'd like to help.
Let's first make sure both devices are up to date. As of this reply, the current version for the iPhone is iOS 13.4.1, and the current version for the Apple Watch is watchOS 6.2.1. The following support articles provide help with updating:
Update your iPhone, iPad, or iPod touch - Apple Support
Update your Apple Watch - Apple Support
Then go on your iPhone to the Watch app > Calendar > and make sure you have this set to Mirror my iPhone.
If you still have issues, let us know if the account you're trying to sync is an Exchange account.
Hope this helps.
Best Regards.