How to disable the automatic backup feature on Samsung J7 Prime – urgent!

My phone is a Samsung Galaxy J7 prime with Android 7. I am trying to make a backup of my personal data from the phone to a USB drive via an OTG cable.

However, every time I install the unit, the files in my phone application (com.whatsapp, .nomedia, LOST.DIR, com.symantec.mobilesecurity, etc.) automatically start backing up the unit, which I do not want. How can I disable this function and only copy those files to the unit that I personally selected?

Any kind of suggestion or help will be appreciated!