While "overhead" is an overloaded term, in practice it looks like:
1. Too much documentation, blog posts, spreadsheets (designed for management optics). Every one of these artifacts takes dev time.
2. Excessive stages in CI pipelines, internal tools, saas tools usage (designed for engineering promos). Every one of these takes dev time.
3. Excessive features (designed for IC and management promos)
4. Excessive amount of time spent in promotions, stack ranking, and performance reviews (designed to make management useful)
5. Excessive time on making agile work such as time on Jira story points, backlog grooming, retros, meeting minutes, agendas, scrums (designed to again, make management appear like they are doing something).
6. Excessive number of management layers (manager, sr manager, director, sr director, sr sr director, associate vp, vp, svp). Every person on this ladder is overhead*365 days a year.
All of these are entirely a problem of management layer overhead.
The only and only thing that works in a tough environment is few "skilled" managers who are still very technical and can align people and teams work towards specific goals.