Hi and welcome!
First of all, thanks for your support! It's much appreciated
Exporting the settings and importing on another Mac (or the same) is possible via the
defaults command in Terminal.app. To export the settings you'd use
defaults export app.mp3tag.Mp3tag ~/Desktop/Mp3tagSettings.plist
and to import you'd use
defaults import app.mp3tag.Mp3tag ~/Desktop/Mp3tagSettings.plist
defaults delete app.mp3tag.Mp3tag SecurityScopedBookmarks
The last command is necessary to remove data that is specific to the Mac you've exported from.
Please note, that Mp3tag's settings are also part of every Time Machine backup you're doing and are restored if you restore from a backup.