Have Alba do an ECU reflash for you. That's the only way to increase top speed. Kawi has the rev limiter set from the factory, which cuts the top speed at around 50 mph.
Alba reflash: Kawasaki Teryx & Teryx 4 2014-2021 ECU Re-Flash | Alba Racing
Alba reflash: Kawasaki Teryx & Teryx 4 2014-2021 ECU Re-Flash | Alba Racing