Hi that's normal for the first week or so, I was getting less than a day battery use, then it went up to a day & a half now its at 2 days & 22 hours, I've turned of certain vibration settings & AOD, auto detect activities & active times but left on everything else like heart rate reading, Samsung health, Bluetooth, WiFi, LTE.
Once the Google play services calms down & stops draining battery it'll get even better, I went through the same process with my watch 4 classic 46mm LTE.
Just give it some time.
(I've also done a factory reset)
Hope this helps.
(I've had my watch from the 7th August)

