I have been watching this thread intensely. I have the Garmin Epix and I love everything about it EXCEPT the HRM. Being heavily tattooed on the forearms, the current generation of Garmin sensors does not read my heart rate properly and I am bound to a chest strap. In my testing (putting it on in the store) the Ultra seems to get a really good read of my Heart Rate. Battery was a concern, but my level of activity matches yours. Maybe 1-2 hours a day with a long run on Sunday maxing out at 3 hours.
I am also married to the Apple ecosystem. Iphone, Airpod Pros, Homepods, Mac, Ipad and Apple TV (holy heck, I sound like a fanboy) So I am hoping that the Ultra will pair nicely.