One caveat one this. Once you add your Apple Pencil to Find My, you can no longer turn off the Apple Pencil.
On prior Apple Pencils, and on an Apple Pencil Pro that is not registered to Find My, turning off Bluetooth on the connected iPad results in the Apple Pencil losing its connection to the iPad. This immediately shut down my two prior Apple Pencils (Lightning type and magnetic type). They would keep their charge for months and months in a bag; otherwise they'd drain down to zero in just a week or three.
The Apple Pencil Pro, though, seems to stay on for about 30 seconds after turning off Bluetooth, but then it too will shut down. Once you turn Bluetooth back on on the iPad, the Apple Pencil will no longer be accessible. In Settings, the iPad will say to place the Apple Pencil in its iPad charging spot to re-connect. It will then keep its charge for a looonnnggggg time.
Registering the Apple Pencil Pro with Find My seems to alter the settings so that it never shuts down (makes sense, I guess). I've not yet determined how long the new Apple Pencil Pro keeps its charge like this. I'll be checking that.
So, you have to choose whether to be able to always find your Apple Pencil or to keep it in your bag for weeks unused and always have it charged. (I'd charge my Apple Pencils to 80% before turning them off before, FWIW).
Note: I could add my Apple Pencil Pro to Find My without unpairing it. Just clicking + on Devices in the Find My app on the iPad guided me through this (you just put your Pencil back in its charging spot and authorize the addition to Find My.)