MicrosoftWendyHaddad As a program manager, my experience (constantly evaluating, testing ideas, and using it on multiple plans daily) using Planner is not well suited when there are multiple project managers, budgets, teams, etc. The reason is that projects can be managed by other teams/PMs, you may want to weave in dependencies that are cross project, resource management is only per plan, and neither the built-in timeline nor roadmap views are useful as currently designed. The best available tools that help manage program and portfolio level plans are those like PPM Express, which aggregate plans from Planner Premium, Project Desktop, Azure DevOps, etc. into a view that can show the full picture of complex programs. Hands down, no comparison. Adopting the approach you show is good for smaller efforts. I would suggest outlining with emoji/icons as well for Risks, Issues, Deliverables, Action Items, Key Dates, WBS, and Stage/Phase. It is a tool for program managers at that point, and assignees will tend to get lost in the details. Using the tabs/sections at the top of the project to separate non-schedule/task elements would make the schedule/plan/task list better.
