Perhaps just improve the quality of the pads, plus learn to ride so that you need to brake less. This takes some time, the fun of running fast is very seductive. But you simply get off the throttle, or stop pedaling a bit sooner when you know a stop is coming. I took some time for this too myself, when I went from lots of 30 mph e bike riding, to a 90 mph gas scooter. At first, I used a lot of brakes. Now I just coast farther.
A bigger rotor might be a good first modification too, just the rotors and some spacers for the brake mount. But again, modifying how you ride may be all you really need.
Right now though, a noisy stop indicates the pads at least are roached.