[nagisa]

While I don't have any suggestions on how to look at the relevant metrics, a big part of the issue is the parts selection and having them power off properly.

1%/h is just 0.5W (for a 50Wh battery) which isn't a lot, but fail to bring a component or two to shutdown or sufficiently low power state and you'll observe exactly this behaviour. Of course some drain is going to be almost inevitable just to keep memory contents sufficiently refreshed, but with proper power-saving states memory can go appreciably below 0.5W.