A lot of smart watches require some form of cloud API through a major mobile OS, and I can't think of any that don't. Direct local sync is possible with Gadgetbridge though.
There's also this guy who modded the ubiquitous cult classic Casio F91W: https://n-o-d-e.net/datarunner.html
Personally I like the Apple Watch, I have the LTE model because I like to leave my distraction rectangle at home when I can and still be available for calls. I do have a few Casio's as well though, an A168 which is basically an F91W clad in metal and with a better back light, and also a Casio CA53W, the calculator wrist watch.