UEFI bios on 7070 optiplex won't recognize external USB DVD drive

I am trying to get a 7070 Optiplex to boot from an external USB DVD drive, but having a hard time to get the system to recognize the optical drive. This is a test machine, so I run CentOS and Rocky linux and switch back and forth between the two.

I had Rocky Linux 8 and CentOS 7.9 successfully install from a network boot DVD on the same machine. Both times, the system recognized the external drive and let me do a UEFI boot from it, and the install went fine, no issues.

This 3rd time around the UEFI bios isn't recognizing the external drive and is only giving me the local hard drive as an option to boot from. On the previous installs I also had inet 4 and inet 6 network boot options too, but they are no longer given as options.

I tried resetting back to both the factory settings and the BIOS defaults, hoping to get back to a good state, but that did not work.

Any suggestions how I can get the system to recognize, and boot from, this external USB DVD drive?

Thanks,