What stage can and cannot tell you
Stage gives context for the employer, but it is not a job description. Two companies in the same stage can ask an FDE to do different work. One role may focus on production delivery for customers. Another may combine technical delivery with product feedback, presales, or team building.
Read the posting for the decisions you would own, the customer or team you would serve, the coding expected, the travel and work location, and whether the role is an individual contributor, technical lead, or people manager. Compare those terms directly rather than using stage as a shortcut for seniority.
The dataset also includes company size bands, but size and stage are separate labels. A large public company may have a small team hiring for a focused role. An early company may ask one person to cover several kinds of work. Those are possibilities to check in the posting, not conclusions from the stage count.