So the more I research these external USB CD players, I've learned that the cheap ones seem to require a head unit that uses Android as it's operating system, specifically Android version 4.4. These cheap ones are the ones that plug directly into the USB port and are also powered by the port at the same time. They have no other power requirement.
On the other hand, the more expensive versions of these drives can work not only with Android powered head units, but other operating systems as well. There is one that you can load the information from a total of 12 CD's and it stores the information on a flash drive accessible from the front. So basically, there is a CD drive, an interface to store the information from the CD media onto a flash drive, and the USB interface from the flash drive to the head unit. It is unclear whether this particular unit also requires an additional power supply, but there are additional connectors and wiring that it comes with it along with an infrared remote control and a front control panel and display. Here is the link to it:
https://www.amazon.com/Premium-Drive...4-dc28e6d374b3
This would be the one I would purchase for my old lady's RAV4 since her head unit is not Android based being a 2019 model with the JBL 11-speaker system.