This is not a proper test for chess memory. The point is that chunking is learned. A strong player has a single entity in their mind that describes a complex pattern. Magnus may have many more of these available than his opponents, letting him memorize and recall chess patterns more easily.

The same is not true for other things to memorize. "Memorizing highlighted circles on a grid" is quite different from chess patterns. So I don't think this test can be used to say anything about his relative capabilities.