I found a few old threads talking about how the built-in screen controller doesn't allow for 3rd party flight apps. Is that still the case? If so, is there a way to flight plan on the DJI Go app? I'm aware of how to set waypoints, but I don't want to fly the drone twice to capture photos. I would also like to set up a grid to make 2D maps. Is that possible with this controller or do I need to find out where to get a controller that doesn't have a built-in screen?

Hi there. Thank you for reaching out. Yes, the Phantom 4 Pro remote controller with a built-in screen does not support 3rd party applications. Also, we cannot perform the said 2D maps with the DJI Go 4 app. We suggest you use a standalone RC without a built-in screen and download the GS Pro app on your mobile device to achieve the said feature. Hope this helps. Thank you for your understanding and support.

You can download the .apk files and install from there, I used the APKPure site. There are tutorials on Youtube. Not sure if it will invalidate any warranties.