My setup is exactly as described in the article with the exception of Focus. The only Focus I use is Do Not Disturb and that is set to be daily from 8:30 PM to 5:30 AM. No medications are scheduled for that period. I did not have Notifications allowed from any apps except for Time Sensitive Notifications (which should include Medications). I have now added Health to Allow Notifications From.
This is all incredibly frustrating. Yesterday I got Medications Reminders on both my Watch and iPhone. Today, I only got Medications Reminders on my iPhone, not my Watch.
Since I had already set up medication reminders using the Reminders app which worked very well, I think I'll give up on the Medications app/Health app section, and just rely on the Reminders app. It always works while Medications Reminders has turned out to be surprisingly unreliable.