What can I do if the monitor’s own menu stops opening after a DDC power command?

Stop repeating the power or backlight command and use the monitor manufacturer's recovery guidance. Some monitor firmware handles these commands poorly: brightness adjustments may still work even when the monitor's own on-screen menu no longer opens.

If the problem began when brightness reached zero, turn off Turn off screen when combined brightness is set to zero under Settings > Displays > [display] > Device Control > Device Control Settings…. This prevents ordinary combined-brightness adjustments from automatically repeating the screen-off operation. It does not itself repair the monitor's menu.

A monitor factory reset may help, but it is not a universal fix. Prefer the monitor's built-in reset procedure when its menu is accessible. BetterDisplay also offers Device Control > Display Factory Reset when the DDC feature is available. Its warning explains that some displays do not handle the reset command correctly.

Before resetting, record any accessible brightness, contrast, color preset and calibration-related monitor settings: a factory reset can discard them. Confirm that the physical display actually reset before accepting BetterDisplay's follow-up Reset Values action, which resets the app's stored DDC values separately.

Do not assume that a successful reset on another model establishes support on yours. If the menu remains inaccessible or the fault returns, contact the monitor manufacturer rather than repeatedly sending raw power or reset commands. See Device Control for the reset actions and DDC Control for device-specific command support.