von Ken Task.
An mbz (moodle course backup) is really a tgz file that contains xml files that map to directories ... like files.xml mapped to files directory.
An mbz will not work for what you seek.
How about, since you still have access to the moodle right now, do your copy and paste stuff into the new LMS while logged onto that.
Not a moodle plugin and I have no first hand experience with the following but did find the following via Google:
https://convert.guru/files/mbz
Use at your own risk! :| Good luck!
'SoS', Ken