All gaming tools
PWM Flicker Test
Check your screen for PWM backlight flicker
JavaScript in a browser cannot detect PWM (pulse-width modulation) backlight dimming directly — it has no access to how fast your backlight is physically switching on and off.
Point your phone camera at this panel in slow-motion / high-frame-rate video mode. Horizontal banding rolling through the recording means your backlight uses PWM dimming.