Your approach looks good to me, except you may be missing one thing: what I call “Workstream projects.” It answers questions like, what do we need to do this week without requiring you to open all 100 projects. See #2 “Workstream projects, one per sub-team” in this post (below). Although this post is describing a marketing requests workflow where the requests are each tasks not projects as in your workflow, it’s the same with regard to workstreams: