Have you checked out anything from Garmin? I have a Forerunner 955 that I really enjoy. It does all my workouts and Is really good for running which is the primary reason I bought it. Another thing I like is that it can do NFC payments and has around a week of battery life depending on how much I use it. It is expensive though and the display isn't as good as the Apple Watch but thats why the battery lasts so long.
I know the Apple Watch is a really good option although I'd worry how well it would work with GOS. Maybe someone else can share their experience with that.