Thank you. Yes heave ho was one of my inspirations ;)
Really weird, does it only do that in my game or all over your computer? And which controller did you use?
I can't say I've tried a WebGL game with controller before but it doesn't do this with steam games. usually connecting the controller hides the mouse. I'm just using an xbox controller with a usb3 cable.
However, while writing this I figured I'd try a ps5 controller and it works totally fine!!! so it must be the controller.