I would have a look at Garmin devices as others have said. I had a swim2 for a few years that my daughter now wears since I got a Descent mk2i. I needed a dive computer with good range on air integration to watch my daughters gas next year when she’s old enough to get certified.
As for fitness tracking I have nothing but good things to say, although the few and far between firmware updates are a drag, and I’ve never seen a new feature unlocked, the fact that the data I get based on the specs I purchased is great, consistent, and the damn things just always work. ___
Blinders are a powerful thing unfortunately.