by Ken Task.
Your server is linux. Why are we testing .mbz file contents on Windows using 7zip or whatever?
Use native ... native to Linux and your server in partiular.
To test, copy the backup.mbz file to a test directory.
cd /path/to/that/test/directory
Then tar zxvf backup.mbz
See a moodle_backup.xml?
See a files.xml? In files.xml look for a reference to that video.
That video would be in files directory of the un-compressed archive and in subdirectories structured just like moodledata/filedir/
The filename doesn't have a filename extension on it, but ... if you what the filename and extensions is supposed to be let's see if the video plays:
cp hashnamedfile /var/www/html/ - or wherver ever you have document root and a browser can see files - to a typical filename.ext .... somevideo.mp4 ... whatever the extension should be.
Then use a browser and go directly to https://yourmoodlesite/nameofvideo.ext
Does it play?
'SoS', Ken