Bluetooth unavailable after 13.5.1 upgrade on iPad
After the 13.5.1 upgrade, Bluetooth has become unavailable. Can’t use any of my external devices/keyboard, headset..any known fix
Hello,
Try resetting iPad's network settings in Settings > General > Reset > Reset Network Settings. Be certain you do not select Erase All Content and Settings as this will erase all of your information. It is a good idea to perform a backup of your iPad prior to resetting its settings.
If you can't connect a Bluetooth accessory to your iPhone, iPad, or iPod touch - Apple Support