Apple’siPadOStook a big step towards making the iPad line-up a good portable computer replacement. However, there are still some issues in both the software and the hardware that need to be sorted out. For starters, the iPad keyboard doesn’t have a row of function keys. This means if you want to adjust the screen brightness of your iPad you are dependent on the Control Center. Moreover, there’s no built-in way to adjust the backlight brightness for the Magic Keyboard either.
However, it seems that Apple is working on getting around this problem. According to references found within the source code of iPadOS 13.5.5 beta, the company is building shortcuts to replace some of the function keys. Specifically, 9to5Mac notesfinding evidence of shortcuts to adjust brightness levels of the screen and the Magic keyboard.
It makes sense for Apple to add this functionality to the iPad. After all,it already has the required UI in place for handling keyboard events like this one. If you connect a third-party keyboard with function keys to the iPad, you can use the brightness keys to adjust brightness of the iPad screen.