I was commenting based on my recollection of this article. Granted it's for AMOLED, so it may not apply to microLED.
In this regard, AMOLED displays have a strong disadvantage. If you feed less voltage to the organic diodes, not only do they limit their brightness, but their color also changes, so that there might suddenly be visible differences in the color reproduction.
Based on that article, non-PWM based solutions seem to be very hard to implement for smaller devices anyway.
Apple has already unfortunately abandoned PWM flicker free displays on almost all their devices. So I have no reason to believe this will change.