After leaving my Samsung Galaxy A-30 phone (with Android 9) for a few hours unbelievably I understood all of my internal storage is cleaned! I don't remember that I have installed any suspicious app but I just attached a USB flash to my phone for some data transferring last day.
Now I just want to know what happened to my phone's internal storage data, is there any system log file for Android 9? How can I find if an app with storage permission has done this?