Choose or Lose. You have to take charge of your choices. Ask yourself which projects will give you the best opportunity to learn and which projects will allow you to work with the best people. And then lobby to receive those assignments. You Can Say No.
Most bosses care about looking good.
So they tend to put their most experienced people on their most important project. But career activists want to do new things. Well, it's easier to turn down a project than most people think it is. You may have to reframe the project, or your role in it, but you can usually get more out of it. Of course, if you say no too many times, there might be problems.