There is no need for more than one Pointing-Device on a PC
I thought so years ago, but with Multi-Touch you could save that problem.
Or with game-pads.
Problem is Windows and or the mouse driver. Touchpad and mice and also stylus pens on graphic tablets are all fixed to only on cursor and you only could focus on one UI element at the same time.
So your "mouse" would be something like an Audio-mixer-turntable device, or a color-grading-device. And they use USB / midi and I guess they nearly the same as game-pads and joysticks.
You could create a virtual mouse. via Joystick, via virtual joysticks or via virtual track-pads.
https://www.codeproject.com/Articles/482229/Ultraping-Paddle-Game
you also could use a mobile-phone, use USB-OTG use a mouse on that and use networking, so one of your players would have something like a remote-mouse
nearly same problem, I guess
I wanted to use gyro from the Nintendo Joycons, but on PC only buttons and stick are useable without heavy hacking. So I tried it with Smartphones and networking.
https://forum.thegamecreators.com/thread/223207
try virtual track-pads in some corner of your game, moving the finger would be moving the player, tapping would be "fire". Maybe per player to fingers for moving and if only one finger, that would be fire and move or something like that