Have you had discussions about this with your manager, and made it clear you're interested in working on different things? How did it go? You probably have more agency in this situation than you think.
DON'T SAY: "I want to work on greenfield projects."
DO SAY: "What would you like to see from me, so that six or twelve months from now I'm able to be a part of greenfield projects?"
This applies to asking for pretty much anything from management.