Sideloading apps is not a feature of iOS. It is also illegal unless the app explicitly allows it in their license. If you need to be able to side load apps, you

Sideloading apps is not a feature of iOS. It is also illegal unless the app explicitly allows it in their license. If you need to be able to side load apps, you need a device intended for this purpose. Regarding data, all user data on iOS is backed up either through iCloud and/or on your Mac.