Have you considered simply finding things to work on that you'd actually find interesting? They don't have to be projects that are officially sanctioned. I'm doing mostly backend coding on a legacy app, but certain parts of the app and our infrastructure make that harder. So when I identify something I don't like, I've started chipping away at making it better: logging, deployment, testing, builds, etc. Surely something at Google is suboptimal. You can seek it out and make it better.