Just interested in hearing about your path. I can easily see myself being stuck in the “senior engineer” position just grinding code and not really moving up or growing, whatever that means. Ideally I make moves that allow me to think about running a successful business.
You could consider something in business or management if you’re interested in taking your career down that path. Alternatively if you have an interest in some really niche topic, you could study that formally, advantages of that is that you can end up combining your current knowledge/skills/experience with a new set of skills and knowledge which could be useful in being able to develop a completely new product or service that doesn’t exist yet. “Multipotentialites” - often are good for having knowledge in multiple subject areas, and are good for coming up with new ideas that intersect between specialty knowledge/skills that wouldn’t usually go together.