The cheap ones cycle at 60 Hz.
LEDs are flashing, as do old light bulbs and fluorescents. However, tungsten in old light bulbs never cooled between bursts, while fluorescents stimulate gases that do shimmer, but still allow for a form of light continuity.
LEDs are strobe light equivalents. You want 120 Hz refresh, and life is then good.
So LED’s can’t run on DC without converting to AC? I did not know that.
I honestly thought you could convert the AC power to DC before it hit the LED.
This seems to suggest that LED’s can produce pure DC light, with no flashing:
https://www.sunlitest.com/faq/do-led-lights-run-on-ac-or-dc-current/