This is a sweeping opinion.
I have two aunts who are now professors emeritus, and an uncle who was a professor but switched careers in his 40s. All three would say teaching and interacting with bright young people was a joy and a privilege. Their gripes revolved around administration.
Their subjects were psychology, ethics and philosophy, so perhaps attitudes are different in STEM subjects where professors are head down in their own research. But then, don’t their grad students do the lecturing and marking of the undergraduates?