Hello, this is Emily.
Yes, you can use a Plug and Play external DVD drive with your HP laptop running Windows 11 S mode. The PnP technology allows the device to be recognized and installed automatically by the operating system without requiring any additional software or drivers. You should be able to use any brand of external DVD drive that has PnP technology. However, it's always a good idea to check the manufacturer's website for compatibility with Windows 11 S mode before making a purchase.
Worst scenario you can always get out of S mode. S mode protects your system not because it is safer or better, but by limiting where you can download apps, hence not as flexible. In case you want to switch out of S mode, you can use this instruction: https://support.microsoft.com/en-us/windows/swi...