Definitely a short but high quality E-book is a good route to go.
Then go to an Affiliate platform like JV Zoo or Warrior Plus and place it for promotion there.
Also going to Warrior Forum to Market your E-book is a good option. They have their own Marketplace to get sales from that.
Just make sure that the E -book is transparent. If you have a whole lot knowledge about Crytpo but little trading or investing experience please disclose that !
The best scenario would be if you have real experience with real success in investing/trading Cryptos and highly knowledgeable. And then write and market the E-book
Nice tips, Rob!