Milestones on a roadmap

What is the challenge?

I need a high-level roadmap to summarize multiple workspaces, initiatives, and key milestones. Currently the gantt chart does not contain data at a higher level than the schedule, and the custom roadmaps do not allow me to insert milestones from a schedule

What is the impact?

I am struggling to get a summary view that allows me to effectively communicate status and key milestones to executive stakeholders without too much detail.

Describe your idea

I would like more cusomization options either in the custom roadmap (to include milestones) or starter roadmap (to use initiatives and schedules as parent grouping instead of bars on the gantt)