Maximum ΔE*00 < 2 is good for professional work as advertised by monitor manufacturer
Also it’s wise to take a look on grey range, against profile and also against true neutral grey. Neem’s seems OK against display profile.
Color distance against a “reference” can be two times bigger when you compare some grey to another grey. It’s a way to see numerically if some grey is a bit green but within tolerance to reference but another grey is pink, also within tolerance. Color distance between those greys, (= what you’ll see in your screen) can be much higher than error in a particular grey to its reference.
RGB + gray balance combo in report , then look for “range a*b*” is a way to measure “amplitude” in color oscillation in neutral axis.
Bad range and banding caused by calibration or color management can be a PITA if you need to work with B&W.