Color range

Full and limited range describe which signal code values represent black, white and the levels between them. Limited-range video reserves values outside its nominal picture range; full range uses a wider nominal interval. This concerns the assignment of numbers, not the width of the color gamut or the signal's bit depth. Apple’s video-range documentation

The sender and receiver need to agree about how those numbers should be interpreted. BetterDisplay can show range labels in its Color Mode choices, but seeing an available label does not confirm how the monitor itself is configured.

See Color mode and Bit depth to distinguish these properties. The Color Mode article explains the relevant options.