Since I upgraded my iPhone 7 Plus to iOS 13, I've noticed these issues on my series 3 watch:
– I can't use shortcuts. It tries for a minute (says "checking with the app"), then says 'Your shortcut says: "Sorry, Shortcuts is currently unavailable on Apple Watch."
– Can't use location-based reminders. I get "The calendar that tracks your reminders doesn't support location-based reminders." Well, Watch, my calendar did support them until I upgraded my phone, so I don't think it's my calendar's fault.
– Watch won't unlock my laptop. I still have "Allow your Apple Watch to unlock your Mac" checked in Security settings on the Mac. It sits there for a few seconds like it's trying, but it consistently fails, whereas before the upgrade to iOS 13 it worked probably 80% of the time.