Might be related to those sleep state stuff that microsoft keep pushing. I think LTT has a video about how it causes battery to drain while off. I think the solution was either shutting it down while unplugged, or while plugged in or something. If you always shut the laptop down with the charger plugged in try to unplug the charger before shutting it down and see if it makes a difference. Or the opposite. I don’t remember which it was.
In ~/src Mostly because I’m too lazy to type “source”.