In DFU mode it is more complicated, because the application has to run a different process to access the information.
Of course, the first method of recovery is in extreme emergencies. The other ways are through iTunes and iCloud. In the first case it is not necessary that the device works , that is, if your device has suffered any damage it can work as long as you have a backup on your Mac or PC.
To be effective, the backup should have been done before the incident occurred. The lost data will be found if the backup was done properly, any small damage to iTunes will cause the mission to fail.
It is recommended to use when the device is damaged, when it can no longer be synced with iTunes, and when it has been recently restored.
In the cloud it’s similar to iTunes, although the device doesn’t work but you need a backup in iCloud. Also if you’ve lost your device along with a login with your Apple ID. PhoneRescue asks you to have iOS 8.4 or higher, which will not be a problem.
This method is more effective when all the information has been saved in iCloud and you don’t depend on iTunes. If you believe your device is infected by a file that is malware, this method is also recommended.