By virtue of being a junior, as you're just picking things up, you have to be flexible, malleable and open to new things. Anything that seems to work is amazing. Then you start to form the "it works" vs. "it's built well" intuition. Then your skills and opinions start to calcify. Your beliefs become firmer, prescriptive, pedantic, maybe petty. Good code becomes a fixed definition in your head. And yes, you can be very productive within your niche, but there's a quick fall-off outside of it. But then, as you grow even more, you realize the beliefs you held dear are actually fluid. You start to foster an experimental side, trying things, dabbling, hacking, building little proofs-of-concept and many half-finished seedlings of ideas. This, which the OP identifies as 'Staff level', is for me just a kind of blossoming of the programming and hacking mindset.

With LLMs, you have to be open to learning their language, their biases. You have to be able to figure out how to get the best out of them, as they will almost never slot easily into how you currently work. You have to grow strong intuitions about context, linguistics, even a kind of theory-of-mind. The latest "Wait" paper from stanford shows us how such tiny inflections or insertions can lead to drastically superior results. These little learnings are borne of experimentation. Trying new tools and workflows, is as well, utterly vital, but per every emacs/vim or tabs/spaces debate, we see that people don't do well to branch outside of their workflows. They have their chosen way, and don't want to give others the time of day.