I don’t know that anything about concentration is necessarily magical. I mean, in common English, concentrating on something isn’t magical at all (us non-magical folks concentrate all the time), so I feel there would need to be something noting it as different from regular, real life concentration.
Also of note: in the Concentration rules it list what can break Concentration, then states the following:
“The DM might also decide that certain environmental phenomena, such as a wave crashing over you while you’re on a storm-tossed ship, require you to succeed on a DC 10 Constitution saving throw to maintain concentration on a spell.”
So DM is not any of the listed ways to lose Comcentration, nor is it an environmental phenomena, so, RAW, it doesn’t break Concentration.