Usually, either:

the villain starts the plot, or

something affects the protagonist, or

he's called to action, or

he's dragged into the plot.

Where are the protagonists who start the plot on their own will?

Examples:

Tony Stark (Avengers: Age Of Ultron, 2015)

Furiosa (Mad Max: Fury Road, 2015)

Lou Bloom (Nightcrawler, 2014)

Professor (Money Heist, 2017-2021)

Note: I realize that many biographies fit this. It would be interesting to see fictional examples though.