A Bluetooth keyboard for the iPad is expensive. Whether is a keyboard folio or an independent keyboard it is expensive. And yet another accessory to carry around with your iPad.
Keypad is a MacOS application, that can work like a bluetooth keyboard for the iPad. It does not stop at being a keyboard, use it to play media on your ipad, and copy paste text from your mac to the iPad. You can now control media playback from the iPad, including volume control.