I was thinking to use this method, but when I tried to use the edit command, I got an empty text editor

Does this edit basically "merge" my additions to the service?


Its usually better to use this:
    systemctl edit bluetooth.service
and then just add the lines that you need to override.

[Service]
ExecStartPost=/usr/local/bin/fixaudio.sh

this creates a drop in file that means that you do not have to worry about any improvements
to bluetooth.service that could be updated by fedora.

Barry