Index smart scale vs Index S2: body fat inaccuracy and smart metrics

I used the first Smart Scale for many years with no issues, but i had to replace it because of the sudden battery draining that was not possible to fix. So i bought the Index S2 and after a couple of months usage i have much more issues than before:

The body fat increased from avg 23% to 27% with no reason from the first to the new product in 1 day. Which is wrong, the old one or the new one? at the moment i am confused and no, i can't compare it to anything else as i expected to be this product my source of truth. 

the smart metrics are not available for the extra user i have. only weight and bmi. Tested many solutions but they don't work. my user correctly collect everything but the second one only the basics since the first time. Of course also in this case, the extra user collected everything correctly with the first smart scale. 

I am so much disappointed by this product and i am considering if it makes sense to keep my Garmin environment at all?

thanks