how can i transfer data from IOS 14.7 to IOS 14.6

How to uninstall iOS beta software; click here --> https://support.apple.com/HT203282

"Remove the developer beta by restoring your device

To remove the developer beta immediately, you need to erase and restore your device. Then—if you have an archived backup—you can set up your device again from that backup.

Note that backups created while using beta software might not be compatible with older versions of iOS. If you don't have an older backup that was made using the current version of iOS, you might not be able to restore your device with your most recent backup."

You cannot restore a backup made with a beta version to a lower version. That’s why you should make a backup before installing a beta.