The official Apole released version of iOS 15 came out on Monday September 20.
You can choose to stay on the beta versions OR if you want your iPad to be on the official release, and have to wait for later official, iPadOS updates, you would need to search online on how to remove a beta to get your iPad onto the officially released versions.
Part of getting on the officially released versions of iPadOS 15, involves backing up your device, wiping your iPad clean, starting your iPad as a new device and let install the official iPadOS 15 version and attempt to restore from backup.
You need to look up the exact procedures to do this online.
I have no clue.
I believe the backup needs to be one made before you started running the developer or public beta.
I am not sure if restoring from a backup made from a developer or public beta will work, or not, once your iPad is running the official version of iPadOS 15.
You have the option of just staying on the developer or public beta, I believe, though.
You will need to search online to get your answers and proper procedures for installing the official release of iPadOS 15.
One of the procedures WILL be to completely wipe the device and start as a new device.
I do not ever get involved with beta software, but seen videos on YouTube that have describe the transition from beta software to official release from past iOS/iPadOS developer/public versions.
Best of Luck to You!
