I'm new to cryptography, just started playing ctf challenges and such about a year ago, so excuse me if this comes out a bit stupid   

But from what I understood, the Signature is the message above signed with the wallet's private key. But isn't that just a way to prove that the private key corresponds to the publicly known private key? if so how is that different from bruteforcing the private key itself from the known keyspace?

Again, thanks for the challenge dude, and sry if this question came out a bit dumb xd