I can't make a transaction because I don't have the private key; I'm just trying to find it.
So the program I sent you a link to can only search for keys for wallets that have already had an outgoing transaction?
Apologies. I mixed things up since the addresses look similar so the hexes I gave you above were for the addresses that sent the funds to the address you mentioned.
And yes, from my understanding (and someone corrects me if I'm wrong) you can only get the HEX pubkey of an address, if it has at least one spent transaction (whether you were the one controlling the private key or not does not really matter).
What are the hints for solving the puzzle exactly? did it mention anything about those pubkeys, or you just went your own way using this program?