I'll second the Adonit Pixel.
The Adonit Pixel Bluetooth smart stylus works across almost every iPad made except the very old iPad 2.
Palm rejection is good!
Adonit's wensite states the Pixel stylus battery life is 15 hours of continuous use. 2-3 month standby
I have this stylus and I have only eeked-out between 7- 8 hours of continuous use. About half it's rated battery life.
It takes about a hour to charge from 0 charge.
So, it's very quick to charge.
To make sure you get the latest firmware for Adonit's Bluetooth Stylii, order one of these DIRECTLY from the Adonit website and not from Amazon.
FYI,
Also, with most 3rd party Bluetooth stylii, there is a "learning curve" to using one.
You have to play with setting up the proper plam rejection angke of your hand for consistent result.
In addition, with Bluetooth stylii that have palm rejection, you need to lay your palm/hand on the screen, first, before attempting to write and make sure to keep your palm down on the screen as you write!
Some users post negative reviews of 3rd party smart Bluetooth stylii when it is clear to users, that use these smart stylus devices regularly on their mobile devices, that other users aren't using these smart stylii correctly and come to a premature conclusion that the stylus doesn't work or is not working correctly or as expected.
Just a heads up if you have never used a smart Bluetooth stylus before.