Use Systemd to start a Headless Virtual Box instance on system start.
dnf copr enable voor/vboxheadless-service
dnf install -y vboxheadless-service
Copy the vbox file (usually just copy the entire directory) into a folder inside /var/lib/vboxheadless/ (created by the install), also make sure to change ownership to vboxheadless:
su -c 'chown vboxheadless:vboxusers -R /var/lib/vboxheadless && restorecon -R /var/lib/vboxheadless'
Temporarily become vboxheadless and add it to the managed VMs:
sudo su - vboxheadless -s /bin/bash
VBoxManage registervm /var/lib/vboxheadless/${PATH_TO_FILE}.vbox
Get the UUID of the resulting VM:
VBoxManage list vms
Now enable the service with the UUID:
systemctl enable --now vboxheadless-service@${UUID}.service
Check to make sure it's successfully up (or just try and remote into it):
systemctl status vboxheadless-service@${UUID}.service