Yeah for sure I experienced the same, the older ultrabook I’ve used seem get similar drain of about 0.8 to 1.1% an hour, upon deep sleep, I asked on discord too, but people seem to suggest hibernation and other methods 
.
My guess is its because of rechargeable RTC battery and the USB-A / HDMI expansion cards, removal of which gave me both runtime and sleep time reduced consumption. At runtime each A card seem to consume 0.5W with no use.
And for the good news
There seem to be a new bios update which is expected to improve battery drain at shutdown probably it’ll also affect the sleep mode too. Try that A cards out and wait for the bios update too.
I have made a thread for soft-access to hardware kill of ports
Has anyone noticed that each of the USB-A expansion card draws about 0.5W? - #2 by Animesh_Sahu as well as default off when sleep/shutdown
How to disable USB ports during sleep or shutdown? (Any OS) but none of them got any answers