Series 5 watch battery drain

I am now on my third new Hermes Apple Watch because on every occasion the battery drains within 10 hours, sometimes less. Is there a major issue with the series 5? I'm not are I can bear to try a fourth as I am convinced the same thing is going to happen. We have spoken to apple support (which are brilliant) on every occasion. They have run diagnostics and portfolios and there is no solution. I love the watch and want to keep it but not if it's not going to work, especially as we have spent so much on it!!