Apple Watch Series 6 44mm not charging

if it was me then I would try with another ac charger, and try with another charging puck to verify if the culprit is one of those or if it's the watch

if the later then I would reach out to their repair services

Apple Watch Service and Repair - Apple Support

or reach out to their official support channels

Get

Support (apple.com)

And

or

Contact

- Official Apple Support

And

or

Contact - How to Contact Us - Apple

Or

Genius

Bar Reservation and Apple Support Options - Apple