There is no "finding blocks" in Bitcoin, it isn't Minecraft. Miners work on "finding a better hash", for whatever block they want to propose. The two actions, creating a block, and working on finding a hash, are separate.
In a "proof of training an AI" blockchain, there would still be a hash linking one block to the previous one, just the proof for accepting a new block would no longer be looking for another (useless) hash.
There is no "finding blocks" in Bitcoin, it isn't Minecraft. Miners work on "finding a better hash", for whatever block they want to propose. The two actions, creating a block, and working on finding a hash, are separate.
In a "proof of training an AI" blockchain, there would still be a hash linking one block to the previous one, just the proof for accepting a new block would no longer be looking for another (useless) hash.