With completely updated firmware and a fresh new battery, my gear s3 was lasting over 3 days per charge. This was standard for several weeks for me. Then one morning i woke up with less than 5% battery and it was still in night mode. I recharged it and then watched it dump 20% in about 1.5hrs. I spent 4 days with every iteration of fixes out there, including using my watch with everything including Bluetooth turned off. Every single power saving feature used. Still it was sucking it dry. I removed my watchmaker app, and other watch face apps, factory reset, recharge, still no luck. It became apparent to me that regardless of what my software was saying, there was some hw stuck in an "ON" condition that factory resets were not disabling. So I ended up opening the watch and disconnecting 3 of the 4 connections not needing to separate the battery from the circuit board. I pressed the buttons to release any potential capacitor charges and left it for 5 mins, put it back together, charged it to full and turned it on. with Bluetooth back on and my weather apps with location services active again, its now discharging at a .68% per hour discharge rate which is excellent. So I had not heard of this being a fix, but its something i have used on Actual cell sites being a technician before I became an engineer in Wireless. Give it a try, caveat is that you will need a special bit to open these cases, they come with new batteries or can be sold separately.