I'm considering a vivosmart 4 coming from fitbit charge 3. I'm looking for a decent activity tracker mostly interested in 24 heart rate and sleep tracking, no real interest in smart watch features. I like the battery life and form factor of both vivosmart and charge 3. I understand fitbit maybe ahead in the sleep area. I like what i've seen of the garmin app and data. I also have come to understand optical heart rate monitors just don't seem to cut it for intense or near intense exercise.
I mostly do elliptical and indoor rowing. I've found the heart rate data during those exercises to be pretty much useless, and don't expect the vivosmart 4 to radically improve over the charge 3. I'd like to be able to use something like the vivosmart all day, but substitute the Heart rate data only during exercises with a chest strap monitor.
Are there any use-cases where something like this can be achieved?