But for now, Apple lags far behind Garmin in terms of fitness tracking for outdoor activities. That's more important to me, and it's more important to people like marathon runners who are more serious athletes than me. But we're also probably a minority of the market; I don't doubt Apple knows what they're doing here.
A modern smartphone can do anything that a 90s pocket organizer could do and more. But Apple Watch still hasn't caught up to Garmin in many important respects.
The fitness industry has a pretty well-developed ecosystem (I grabbed a random 5 year old heart rate chest strap and it paired immediately to the rowing machine). Garmin has seemed to have embraced that for at least a decade. It can definitely use improvement, but Apple has its own thing and it'll give you grief if they didn't have your use-case in mind.
To be fair, others like Fitbit has similar issues. With them you can't even grab detailed heart-rate data.
Not the grandparent poster, but Apple Watch battery life is bad enough that going on medium-length hikes (and tracking it as a workout) requires you to pull out a powerbank and then awkwardly slide the charging pad in between your skin and the watch. Ugh.
(I'm still torn on whether I actually like my Watch; I'd definitely prefer a Lightning port to the custom charging pad that's not even reversible.)
It might be possible your battery has degraded considerably?
Compare to Garmin: The Fenix 6 is rated for 36 hours of GPS activity recording per charge, or 72 hours in a battery-saving GPS mode.
I am a Garmin user and a friend is a PM for Apple and I've had this argument too much to rehash it here :). But it really comes down to depth for the fitness use case (Garmin) versus good-but-not-as-great fitness tracking as part of a more general use case (Apple).
Recent theVerge.com article says the Apple Watch is sending too many people to doctors for further investigation (only ~10% had actual cardiac problems). see https://www.theverge.com/2020/10/1/21496813/apple-watch-hear...
Also the main new feature of the Apple Watch 6, blood oxygen monitoring, was reported as unreliable in theVerge.com review: https://www.theverge.com/21496141/apple-watch-series-6-revie...
and a Washington Post article put down the Apple Watch and the FitBit Sense's blood oxygen monitors:
https://www.washingtonpost.com/technology/2020/09/23/apple-w...