How to permanently delete files from Huawei or Xiaomi smartphone?

Question

Android

Interested in how to properly delete sensitive data from android smartphones. Will a program like shreddit help with the dod 5220.22-m method? How many passes do you need to completely and permanently delete data from the internal memory and sd card of an android device, and what is the fundamental difference between deleting data from these types of ROM? If possible, please explain how ROM works in android and how to delete important information on these types of media. At the moment I do this:
1. I delete the files that I downloaded from the corporate VPN from my smartphone
2. I launch erase free space.

Is Shreddit or DiskDigger suitable for 2 points? They create a large file that fills the entire memory of the device and then delete it. Does this method work for secure deletion of data without the possibility of recovery?

Thanks

Answer 1

If a file fills all the memory with units, then old files, even in theory, cannot be restored. It is impossible to restore the zero that was once, but a unit has come in its place

Answer 2

Yes it works. And the question is easily searched in the search engine