There are no specific rules or tests to become a CTO. Anyone can hold that position. I know of a company where the CEO and CTO were appointed to tick the divers

There are no specific rules or tests to become a CTO. Anyone can hold that position. I know of a company where the CEO and CTO were appointed to tick the diversity box. In fact, US government has even gone to the extent of employing in their administration, a luggage thief, just in the name of diversity. Not joking, search for Sam Brinton who was the head of nuclear waste management in US administration.