Sad I missed the unconference, only found out about it last week and couldn't get signoff to come and meet you...
Selchris is right, the key to education on the UX of blockchain/crypto is about the specifics of the space:
i - In teaching the basic concepts of how the technology works
ii - then showing how it has been implemented historically (exchanges, wallets etc),
iii - Thus demonstrating the UX challenges and opportunities this created (Tx UX, key handling, anonymity, immutability)
iv - And finally showing how designers in the space are currently tackling these problems (eg meta txs / account abstraction)
Quite a lot of the above can be done through links to resources and recommended tasks (as you mentioned in 1)) - The last two steps will require some input from UX Designers to collaborate and educate on the current challenges and solutions in the space.
If the above is done properly, I think it would open up an avenue to solve problem 2) (Attracting more designers) as it could be marketed on all channels as the entry point into the space - I've been designing for blockchain for 3 months and I can't believe it took me that long to discover this forum...
If you would like help in setting up some kind of video series curriculum / collaborative educational resource I would be happy to get involved.
With regards to 3) (Onboarding into design), I think it would be difficult bringing people new to design into the crypto space - The best way to get interested parties up to speed on design is through courses such as https://trydesignlab.com/ux-academy/