As you have mentioned the crypto market cap is way smaller compared to the stock exchanges of even developing nations and hence has a whole lot of whale manipulation,even sound technical and fundamental analysis are thrown out of the window when the whales enter the picture,hence any ML AI algorithm would have a much greater chance at predicting stock indices over crypto in general.
Having said this i still believe that even if in the future we get an insane over the top algorithm developed if it gets popularised too much or a large capital is invested based on the algos opinions then it would create a paradoxical situation,i.e. lets say you are a wealthy investor and your algorithms prediction is a price increase ,if you invest a huge amount now you are the one who is actually being a catalyst for this growth.
But right now there is no algorithm which even has decent accuracy in predicting prices of stable assets let alone cryptocurrencies.