> how do you enable power users to learn more powerful tools already present in the software?

On-the-job-training, honestly; like we've been doing for decades, restated as:

Employer-mandated required training in ${Product} competence: consisting of a "proper" guided introduction to the advanced and undiscovered features of a product combined with a proficiency examination where the end-user must demonstrate both understanding a feature, and actually using it.

(With the obvious caveat the you'll probably want to cut-off Internet access during the exam part to avoid people delegating their thinking to an LLM again; or mindlessly following someone else's instructions in-general)

My pet example is when ("normal") people are using MS Word when they don't understand how defined-styles work, and instead treat everything in Word as a very literal 1:1 WYSIWYG, so to "make a heading" they'll select a line of text, then manually set the font, size, and alignment (bonus points if they think Underlining text for emphasis is ever appropriate typography (it isn't)), and they probably think there's nothing more to learn. I'll bet that someone like that is never going to explore and understand the Styles system on their own volition (they're here to do a job, not to spontaneously decide to want to learn Word inside out, even on company time).

Separately, there are things like "onboarding popups" you see in web-applications thesedays, where users are prompted to learn about new and underused features, but I feel they're ineffective or user-hostile because those popups only appear when users are trying to use the software for something else, so they'll ignore or dismiss them, never to be seen again.

> By corollary, how do you turn more casual users into power users?

Unfortunately for our purposes, autism isn't transmissible.