My grandma has an old LG (Android 6.0) for WhatsApp and a little more. She records some videos and pictures, and the "good ones", I copy to the SD and send by email (to have a backup)
Nevertheless, that week, she had two very important videos for her and a few other things, and as she deleted the unimportant things, seems she deleted all DCIM content. She already receives plenty of junk stuff on WhatsApp. I have found the thumbnails of the missing videos and images, but nothing about the original files.
I know about ADB, I have successfully installed the phone drivers in my Windows so I can access the telephone. I haven't rooted it yet as I am not sure if this would help. Not sure if I could do anything for my grandma's videos.
Shouldn't be a kind of bin in Android as you delete a photo/video?