I have been using a Pebble Time Steel for years even after their acquisition by Garmin Someone corrected me it was FitBit not Garmin thanks to Rebble, a modded firmware that gives it new life, but I would like a smartwatch that can track my heart rate.
I don’t mind using an older device especially if it means a cheaper price. A bonus for me would be if it still had some kind of community around it or a custom firmware like Pebble watches do.
I found an original Moto 360 with a functional battery for about $30 but I am not sure if due its age its functionality would be greatly limited.
Edit: It seems like Garmin and FitBit might be worth looking at. But I wouldn’t know what devices to look at or if there have been any major improvements with recent revisions.
I daily drive it for almost 2 years. Can totally recommend. With the latest firmware it lasts half a month for me.