If your USB-C headphones stop working on your iPad Pro after software update
I had been searching the forums for a while trying to figure out how to get my USB-C headphones to work. It would sometimes work after a restart but not consistently. Anyway, I just figured it out. Under Face ID & Passcode, toggle the "USB Accessories" option to 'on' for "Allow Access When Locked." So far, that seems to be working for me. Hope that helps!
iPad Pro, iPadOS 14