It's time to give up. You've lost the smart... well, voice activated assistant race. It's OK - you've had this happen before with other products.
It's time to admit defeat - Siri is pretty awful, and Alexa (and Google, for that matter) have become much better.
Since you've joined forces with Amazon on integrating (finally) Prime on AppleTV, AppleMusic on Alexa Speakers ... it's time to just throw in the towel and license Alexa on your devices. Merge your technology.
This will put you way ahead of Google. Everyone would be thankful.