That is exactly what I am experiencing. With the Pencil constantly attached, there is no doubt that the iPad battery drains faster than if it was seperated and not paired. It's not as if I am constantly using the pencil, so why keep it magnetically connected at all times?
Probably this is due to what I said here:
https://forums.macrumors.com/threads/apple-pencil-2-battery-life.2153502/page-2#post-26785772
1st gen Pencil = does not try to pair or mantain bluetooth connection 24/7
2nd gen Pencil = works just like the Airpods
Try leaving the Airpods:
a) Unpaired and forget them from ALL your devices
b) Not being used (not in your ears)
c) All nearby devices with bluetooth turned off
And leave the Airpods outside of their charger case. You'll see that in the next hours the battery will go down for the sole reason of being... outside the charger case.
Apple already explained this is due to:
This is an engineering tradeoff. If we were to stop all paging and advertising while the buds are sitting idle on your desk, any time you picked them up and placed them in your ear, we’d take a few seconds to connect. We prioritize the more often seen user situation in which the user leaves the buds out only when they intend to use them relatively soon after.
What happens with this 2nd gen Pencil is probably the same, but the difference here is that the battery lasts more when compared to the Airpods.
This was one of the reasons I sold these headphones. Didn't like the idea of always leaving them inside the charger case, when I prefered to put them next to me, pick them up and resume listening.
A few users reported the Airpods stopped broadcasting only when they were put inside the charger case.
With this 2nd gen Pencil Apple assumes you are using a little and then recharging again right after. This is very stupid since I am accustomed to keep my 1st gen Pencil inside my drawer and weeks later I recharge the battery when it's needed. And if I pair them again the battery is not totally drained, after several days.
With this 2nd gen Pencil there's always a battery drain, according to the posts here. That's why I suggested the use of an EMF meter to see if there's a signal being broadcast 24/7. With the old Pencil this only occurs when a BT connection is established.