Islander_fan said: "In some ways, that kind of role could be harder than a role with more stage time regarding prep. Using the example of Groff again, if he's only onstage ten min, he has to work hard to make every second of them count. Perhaps maybe even a little harder than those with more statge time because they have more chances to get noticed."
Yeah, I think that's kind of the OP's point. What you're describing is exactly the "disadvantage" that the OP refers to. The question is: is all that work enough to give them a leg up on people with larger roles? If they are good enough, then the answer may or may not be yes.
I think this question is often more applicable to the situations where people are misplaced. For example, the fact that Bertie Carvel was placed in leading, despite being in a featured role, put him at a disadvantage against Billy Porter who truly was giving him a LEADING performance.