I find the fit3 very weird & a little disingenuous unfortunately and this is my opinion as it bears a striking resemblance to the Watchfit series from Huawei, both in Hardware & Software, and honestly the Watchfit series has two better features than the fit3, namely GPS & an animated personal trainer for 20+ workout routines,so I don't know what Samsung is trying, but I'd rather recommend the Watchfit series.
You can sideload the Huawei Heath app and it has been proven to be a better accurate step & sleep counter than most brands out there.