In the mini-led industry the clocks are often much higher. That said, you are limited by scan (how many LEDs driven per driver chip), because the clock is divided among the driven LEDs.

Consider that raising the PWM frequency doesn't automatically solve the problems you raise. 20khz PWM can still have audible harmonics, for example. In the mini-LED industry there are actually spread spectrum/randomized PWM approaches to address this, and to help with EMI.