Whats a word for someone who distrusts laymen and believes they always need to leave things to the professionals

Elitist can be put to use here.

regarding other people as inferior because they lack power, wealth, or status

MW

There is a common misbelief among the highly educated that someone with credentials holds knowledge unattainable by others. To wit:

"Beware of the man who works hard to learn something, learns it, and finds himself no wiser than before," Bokonon tells us. "He is full of murderous resentment of people who are ignorant without having come by their ignorance the hard way.”

Gooodreads

Superiority Complex

The professional who believes that only they and other members of their profession are capable of any competence in their domain have a superiority complex.

Social Psychologists explain that

No one likes smug know- it-all friends, relatives or co-workers who believe their knowledge and beliefs are superior to others.

But now these discussions at the dinner table, bar or office might be less annoying. A new University of Michigan study indicates what many people suspect: these know-it-all people are especially prone to overestimating what they actually know.

Even after getting feedback showing them how much they didn’t know relevant political facts, these people still claimed that their beliefs were objectively more correct than everyone else’s. On top of that, they were more likely to seek out new information in biased ways that confirm their sense of superiority.