If you open it up to the TV shows, you probably can get a descent sized list. We get plenty of TV scientists on the various shows, from Fitz Simmons on Agents of SHIELD to Chases dad on Runaways. Not that this particular list necessarily went too deep into the TV side of things, but there's actually a lot to work with.
The problem is always gauging how smart one person is next to someone else. Does Chases dad inventing a machine which can look into the future make him smarter than Karl Malus, who created a means of turning Jessica Jones into a meta human? It's really impossible to say.
The only thing we can say with some certainty is that Shuri is the smartest person in the MCU, because we're told she is.