It's normal that the watch face takes most of the battery. You can lower battery usage by choosing a dark watch fase, lowering the brightness setting (6 on my watch), and choosing a watch face with a dark AOD. Switching AOD off makes a huge difference in battery life.
Sleep tracking works fine with heart rate measurement frequency set to every 10 mins.
With AOD off, sleep tracking every night, above settings and automatic training detection on, my watch uses typically around 25% battery a day. I charge it twice a day while I am in the bathroom after waking up or before going to bed. That way the battery charge level varies between 70 and 100%.