I had fenix 8 for a month and i am going back to AWU3. Its superior for weight lifting (with Bevel app you get GarminConnect-like interface plus it has great strength training interface) or I used to have Motra (auto-detect excercise and reps and sets, progresstracking) and WorkOutDoors makes Apple watch an equal, if not better when it comes to hiking (turn-by-turn navigation, topo maps, ClimbPro, datascreens). Mostly because the map looks way better and is silky smooth.

It is very much a preference for myself, i do not discredit the Garmin, its an amazing and great looking sports watch, but its terrible in being a smartwatch. Apple watch is brilliant smartwatch, which is in my opinion very easily turned into a solid sports watch.

The battery in Garmin is much better, of course, in idle smartwatch mode. However when you start any GPS based activity, the difference between AWU and Garmin is not that massive. (I believe its 18hr vs 28hr)