Katalin Karikó, one of the most important scientists in the mRNA field, was demoted by University of Pennsylvania in the late 1990s because her research was considered impractical and a waste of time. While not a total shunning, it is anyway quite a demeaning experience.

https://www.wired.co.uk/article/mrna-coronavirus-vaccine-pfi...

A generation later, she is considered a good candidate for the Nobel Prize.

Galileo Galilei?