This is a pretty odd take, from my perspective.

If one of my direct reports came to me and said they were interested in working on, say... AI observability (replace with whatever interests you), and that was something I had any influence over (even if only indirectly), I'd be finding whatever way I could to connect my report with that kind of work.

It's all well and good to say that you're in control of your own career advancement, but that's not in conflict with working with your manager on supporting your career development. Even if they don't have anything to teach you, they will necessarily have some influence of your scope/area of work, so it only makes sense to work them on aligning your work with your interests.

I believe everything you wrote about here is actually cooperation between two people, and to the point of what I said, you not actively getting in the way of your direct report's career progression.

> The manager's job is to find you impactful work that a) gets you promoted and b) challenges you in the ways you want or need to grow.

To me, the comment I responded to reads like a manager actively involved in the promotion of a direct report, and in finding a scope of work that the report might find challenging so that they grow. Your comment reads like a colleague helping out another colleague to the best of their ability. Which is exactly what I expect from a manager.