I do find the iPad battery drain to be annoying and inexplicable. When they first came out, iPads held a charge for weeks in standby. New ones drain in a few days, even when background app activity and such are disabled. And you're right that it is frustrating to pick up your iPad and discover that the battery is near-dead, which happens with surprising frequency.
That critique doesn't apply to Remarkables or Kindle Scribes though.
Find my, most likely
Turning that off, or using automatic airplane mode (eg in shortcuts set a schedule to turn on airplane mode daily)
I agree. My iPad 2 could last a month or more in standby. My iPad 8 maybe one to two weeks.
I shut my iPad down when I’m not using it because the passive drain is absurd. I don’t need my iPad to do literally anything when it’s screen off. I have a phone for notifications.