The mcu should be able to sleep between advertisements to conserve power. This should be measured, and if necessary enabled if it is not yet (which I think isn't)
Switching to the mounriver toolchain fixes this issue, as mentioned in biemster/ch592_RF. On a weact studio dev board the power consumption on 5v (so through a step down to 3v3) is 6uA.
The mcu should be able to sleep between advertisements to conserve power. This should be measured, and if necessary enabled if it is not yet (which I think isn't)