Phrase for the belief that your field of study or project has higher merit

I'm trying to find a phrase for the act of rating one's activity greater then another person's activity.

An elementary school teacher might state that reading a chapter with your child is critical but an instructor at a gym might put a greater emphasis on social interaction and physical activity at that age takes precedents. Both are vital for a well rounded child, but each individual rates their activity greater than the others. What is that called?

That is called self-aggrandisement or self-importance (or bumptiousness).

Self-aggrandizement: The action or process of promoting oneself as being powerful or important.

Example: Critics accused him of self-aggrandizement. [Lexico]

This condition is encapsulated in the term bias:

bias - a partiality that prevents objective consideration of an issue or situation

In your example, you could get more specific with "professional bias."