Interesting observation! I actually lower the brightness to about 10-20 % on each display I use (the default settings are ultra high for a sunny day in a fully lit store) and while I have two CCFL panels (a 1000 USD 24" from the past and a 1000 USD 30") blazing at me and both of them clearly use some sort of PWM - they start buzzing audibly below 80-90 % brightness (both in their audio outputs AND even with audio disabled it is heard from the monitor itself) - there never was any visible flicker. And in the CRT days, I saw flicker up to 85 Hz (including). Color wheel DLPs are also pure hell - the image breaks into three separate colors in each eye saccade. Yet, CCFL backlight, buzzing like crazy - and no visible flicker. Enter my latest, fanciest, wide gamut screen with LED backlight - and on lower brightness, it flickers worse than a 60 Hz CRT...

However, luckily, it is not the case of each and every LED monitor - search for "flicker free" or "PWM free" - and it is not some fancy rare unicorn feature, a PWM free IPS display can cost the same or even less than flickering equivalents.

According to this recommendation page [0], there are quite a few monitors with "PWM-free (flicker-free) WLED backlight". The list includes many affordable mainstream choices.

I heard some monitors may revert to PWM below a certain brightness threshold, but assuming the information on that page is accurate, not getting PWM-free monitor is probably a sub-optimal purchase decision.

[0] https://pcmonitors.info/recommendations/

There's some debate about what is flicker threshold (flicker fusion threshold ,I think).

I've seen some academic literature talking about 1000-4000hz , which is far above what most screens do.

Btw I believe BenQ has a display that doesn't use pwm at all .

I had a Samsung Galaxy Note 10.1 2014 LTE edition and that used PWM for brightness, along with a ringing noise at certain rates.