This is a topic close to my heart, and I think you have it exactly right -- situated action, manifesting as a person building something that they actually want to build, is the One True Way of gaining expertise. If you can get to real, self-directed action, everything can ignite from there. And there's only so much you can do to bring someone to the door of that, for sure.

In my experience, what you can do, oftentimes, is remove auxilliary frictions. For instance, at my job, if you want to mess around with code, e.g., to explore an idea, there's a set of some ungodly number of things you must first configure before you can write a single line of code addressing the thing you actually care about. Virtual machines, pre-commit checks, access control, linting, all of this bullshit that, while important for production code in our security environment, is like driving a bicycle into a swamp for someone outside a product team with an intuition they want to test.

Switching domains, the usual state is often like teaching someone to cook by sourcing ingredients from ethnic grocery stores scattered across the city, then preparing recipe components across two days ("simmer for two hours and then chill overnight"). Whatever desire to cook someone might have had will not survive the encounter.

These are the things that can often be greatly helped by scaffolding: here's a skeleton project, here's you compile / deploy it, now go work on the thing you actually care about, and if it needs to get more "official" later, we can worry about it then. Minimizing the delay between curiosity and fucking-around-and-finding-out.

These are general thoughts, not wrt what you guys are doing, which sounds incredibly well-considered. I'm jealous of the participants whose early encounters in the space are so thoughtfully curated :)