lkrupp wrote:
Most any brand external CD/DVD drive should work. The one I would recommend is sold by OWC/MacSales for $55
https://eshop.macsales.com/item/OWC/MR3PDVDR8XT/
That portable one comes with a "High Quality 'Y' type Dual USB 3 (Dual 'A' to 'Micro-B' type) cable", suggesting that it would want to be plugged into two ports (to get more power than one port provides). This arrangement is found on many (though not all) portable burners.
OWC also has desktop CD/DVD and CD/DVD/Blu-Ray burners that have their own power supply, and would only take up one port. The included USB 3.0 B to USB-A cable is easily replaced with a longer USB 3.0 B to USB-C cable (lots of those on Amazon) if this would be more convenient for connecting the drive to a 24" M1 iMac.
Other World Computing – 24X OWC Mercury Pro USB 3.2 (5Gb/s) Super-Multi DVD/CD Burner/Reader External Optical Drive with M-DISC Support