In my opinion, the best way to learn things is by practicing. The Substrate's tutorial (and docs) are already great on that matter.
But I have to say that I miss something around security there. I remember how I got excited when I first met the overthewire's wargames and later the OpenZeppelin's Ethernaut.
Those are exactly the way I like to learn new stuff, coding to solve challenges with a huge dose of gamification to keep me addicted! =)
So, is there anything like that already in production or even as a PoC?
Is so, I'd like to connect with the maintainers to help they on improvements.
And if there isn't, I already have an initial dev team to create a PoC and then try to fund the project by creating a Treasury's proposal.
Any idea or feedback is more than welcome, thanks!
PS: I'm aware of pallet-chaos and it would be definitely used in the project.