Is WR3 More Valuable Than Flex?

I earlier asked if I should start Dion Lewis or Bilal Powell in the Flex, but now I hear the guys talking about John Brown being a locked WR3 this week. Is this enough for him to be the front-runner to put in my flex?

WR3 essentially is a flex. I would play Lewis

https://www.thefantasyfootballers.com/start_sit/dion_lewis-john_brown/?FFBDTStartSit-get_content-261-ppr_picker=HALF