An update:
I tried all of the recommended fixes suggested by Apple Support, Chat dialogue with an Apple Support rep, and in this forum: Unpairing/pairing, diagnostics, etc. No improvement. I submitted a repair request and sent my watch to Apple for repair. It was returned less than 24 hours after receipt by Apple (based on text and email notifications), with no repair. Since my battery is currently ‘functioning at 80%,’ Apple will not even look further and make any necessary repairs. I received the watch back with no improvement.
I’ve since upgraded to new iPhone and MacBook Pro, and I’ve paired my watch to my new iPhone. All OS upgrades have been conducted, and still, my watch charge drains in fewer than 7 hours. (Charge does last somewhat longer if I am not in proximity to my laptop and iPad, but still it does not make it through one full business day...)
This is completely unacceptable. A timepiece that needs to be charged/plugged in for the majority of the day is not a watch. It is a clock!!
Apple needs to acknowledge the problem and take immediate steps to make the fix available to current, loyal consumers.