Can I use the action button to open up the Dexcom g6 app. I’m a type 1 so I would love the convenience of it
Can I use the action button on the ultra to open up the dexcom g6 app to see my blood glucose
It is possible to create "some" shortcuts you can use on the Activity Button on your Ultra. For example, I watched a Youtube video and the guy programmed the activity button to call a specific person from his contacts. You can try to see if you can create a shortcut using the shortcut app on your iPhone to do that, but likely you won't be able to get that to work as that would be integrating with a 3rd party product.
Create a custom shortcut on iPhone or iPad - Apple Support