Run the check
Observe a static test color and record when brightness changes.
Compare desktop, one video, and one game at the same display mode.
Try a different cable or port before changing several settings.
Read the result
Flicker limited to a variable-frame-rate game merits the VRR-specific check.
Limits and next step
The browser cannot read panel power behavior or cable signal integrity.
Repeat the check after changing one setting or connection. Keep a record of what changed before deciding whether the device needs service.