Illustrator CC Duet Display Apple Pencil Pressure Sensitivity Issues with iPad Pro

My old wacom tablet is useless now that they stopped updating the drivers for mac OS, so I'm trying to get my iPad pro and apple pencil to work as a tablet for Illustrator CC. It works, but pressure sensitivity is blanked out when I try and make a new brush. I found an old thread (from 2015) that recommended installing wacom drivers. I installed the latest wacom driver, and pressure sensitivity is now an active selection, but the brush won't work at all with the apple pencil now. If I uninstall the wacom driver, the apple pencil works again, but still no pressure sensitivity option. Pressure sensitivity works in Photoshop CC (with or without the wacom driver), just not Illustrator. I've tried changing the pressure sensitivity curve in Duet Pro, but that doesn't make any difference. I've also tried mirroring and using the iPad it as a second screen, but that doens't make any difference.

Any suggestions? I'd really love to make this work.

Thanks!