Use APKPure App
Get Media Merger old version APK for Android
Merge media files, open-source
Utitily moves /sdcard/DCIM/* and /sdcard/Pictures/Screenshots to user specified folder.
Use this app in conjunction with Syncthing to sync / backup files produced by your phone to your computer to manually delete / arrange files .
Android friendly. Application waits for event from ContentObserver, and only then scan for new files, no ads, open-source, GPLv3.