I believe if you get a PS/2 adapter for PC mice and keyboards you can use an optical mouse actually. I think they might actually also work if you use a USB to PS/2 adapter as well with it with laser gaming mice and or mechanical keyboards. https://www.amazon.com/Total-Control-Co ... B008FZ5PFChttps://www.computercablestore.com/usb- ... o-ps2-male
Here is what one of the adapters looks like with an IBM keyboard and logitech PS/2 laser mouse.
I do own an official Dreamcast mouse however, and meh, it is nothing like modern optical mice but it gets the job done way better than the official controller for FPS games.