Newton was a professor at Cambridge. That was as establishment as it gets.
Your idea is romantic but not really accurate.
Mendel is an example of an outsider making a breakthrough.
It was Newton’s ideas about the occult and alchemy that were kooky.
In fact most of the ideas of scientists of his period we would consider totally crazy.
Btw I doubt Newton lectured on alchemy and how to contact your dead grandmother in the great beyond at Cambridge.
;-)
My point is that I often see posts of the format:
“X is a kook. You can’t believe anything that X says.”
That is the kind of logic that dismisses folks like Newton.