*Raises classroom hand* This happens to me too, but I have to keep it plugged in for hours - five, six, doesn’t seem to make a difference. My iPad 9th gen will show that the iPad is charging on the blank screen, but even if it’s been “charging” for like 7 hours, when it finally boots up it only shows battery at 3 percent. This never happened to me before iPadOS27, it must be something to do with how they’ve changed or how the new OS charges these older iPads.
The problem is that I leave mine to play white noise over night (I only have 1 charger) so it usually dies, and then I have to wait like a day or so to be able to use it again.
This is the first time that I have ever had a major problem with a new iPadOS update.