Either after the latest system software update or the Samsung health app update, the Galaxy Watch Active 2 has awful battery life, about 24-30 hours, according to the indicator but it lasts less than that. I have reset it and the same thing happens, no settings have been changed since I activated it on March. Samsung, take a look a this please. Also, we need more workouts in the Samsung Health app for the watch: cardio, hiit, aerobics, CrossFit, jump rope
I've noticed that with mine too. I'd be in the 90% battery life. When I turn on Bluetooth for an hour our more and it will drain my watch down to 40%. Thats a big difference. Before it would be in the 80s%. Hopefully this can be fixed in another update.
I've noticed that samsung health is draining the battery but also noticed that different functions seen to trigger this. For example the watch could be getting normal battery drain but after i use the timer samsung health battery usage spikes. The same thing happens if I put the watch in good night mode.