I started a thread on this over on the talk.macpowerusers.com forum, but thought I’d post here as I’m desperate for a solution. Sorry to anyone who frequents both fora!
Has anyone had any luck with invoking Shortcuts via Siri commands on the Apple Watch? Even the simplest of Shortcuts simply give the error “Sorry, Shortcuts is currently unavailable on Apple Watch.”
This is a known issue, currently Shortcuts do not run on Apple Watch or HomePod.
Isn’t the latter supposed to be fixed sometime soon? With no word on the former.
(BTW, Rose, 2 HomePods just appeared bei uns…) 
Thanks, Rose. Sad times. Curious that that fact isn’t more well-known—I was surprised to see the number of others complaining about it across the web.
Of course IFTTT can get triggered from the Watch. That, perhaps via Pushcut, gets an automation kicked off on iOS (or anywhere else). However, the Pushcut notification would require you to tap on the phone.
Yeah, there are some neat workarounds. Native Siri Shortcuts on the Watch was a feature I was looking forward to, though, and it seems to have disappeared.
I’m sure it’ll be in a later 13.x release.
I’m not sure it will be. 
Why would you be “sure”?
From https://support.apple.com/en-ca/HT209055 :
After you add a shortcut to Siri on your iOS device, you can run the shortcut by asking Siri your personal phrase on your iPhone, iPad, iPod touch, Apple Watch or HomePod.
It doesn’t seem like a non-issue to Apple if they’re still advertising it as a feature, nor should it be an impossible fix.
I guess if they are publicising it, they should be delivering it… AirPower aside of course.
FYI, I had to remove the colon from the end of the URL for it to work though 
I don’t get why Apple think we all want to talk to our watch; I’d much prefer to tap a shortcut button as was possible with the old Workflow. I really miss that.