I also get the error message for dnsmasq but this system service also seems to be okay. Try the following terminal command
sudo systemctl status dnsmasq.service and you will see that the service is running. Perhaps it‘s a timeout problem when showing this error during the system start. I don‘t know.
The copy of the MoodleBox image seems to be okay when the MoodleBox starts up and shows the Moodle page. You are connected with the MoodleBox wifi, you can open the Moodle page and you can login with the moodlebox user.
I ca‘t reproduce your problem when restoring a course backup on the MoodleBox. I did a course backup in one of my Moodle sites, downloaded the mbz file to my device and restored it in the MoodleBox. The MoodleBox must have installed all Moodle plugins which are used in the course you take. I did my test with MoodleBox 4.2.0, a Raspberry Pi 4B (4GB) and a microSD card with 32 GB.