What qualities to look for in a manager?

Hey scribes and scribe-adjacents =)

So I recently got some very promising Black List feedbacks on my cyberpunk script, one was saying: "A literary manager who handles sci-fi should champion the material."

Basically all reviews I got lately were pointing at: find a manager / producer.

So my question would be: What do you look for in a manager, since I understand that's usually the first step you take.

I know someone who isn't per se a lit manager but loves my story and also believes very much in its success. He has some connections to people in the industry and is incredibly passionate about this and in general extremely hungry and wants to become - as I have tried to make my script - undeniable.

Does a manager have to be plucked into the industry and work for one of the big 3 or 5 agencies or could you just pick someone who will eat, sleep and breathe your script/brand? Kind of like the relationsship that E has in Entourage with Vince.

Cheers and thank you for the advice