Aside from the fact that a strong enough supercomputer won't exist for decades, you're not limited by the speed of UUID generation. Even if you had an infinitely fast supercomputer, it wouldn't speed up your brute force attempts, since you're limited by the speed of the backend. Wherever Tea stores their images, that server has only a limited capacity for responding to requests, far less than the speed with which you can generate UUIDs. That's a hard cap - you won't try guesses faster than that.