Europe's top IP body has found McDonald's does not have an exclusive right to "Mc" or "Mac", even in the realm of fast food because of its status as a common name component: https://www.bbc.com/news/world-europe-49254551

Even in the the US where MacX or McX is a foreign construct, there have been legal cases where people named McDonald/MacDonald are allowed name their restaurants after themselves: https://en.wikipedia.org/wiki/McDonald%27s_legal_cases#The_r...