Yes, in the strictest sense an incorrect proof is not a proof. But at the same time, people often call either flawed proofs or purported proofs formal proofs in a looser sense. You cannot be unaware of this point. You must have understood what was being conveyed. Yet, instead you decided to engage in a nitpick over the meaning of the phrase "formal proof"
Furthermore, your claim that "If you actually come up with a proof, you are completely guaranteed that the proven statement is true." is utterly unhelpful. You know that my point was that a manually verified proof might still be wrong. And yet rather than addressing that point you decide to evade it by an ill-considered nit pick on whether an incorrect proof is still a proof.
So at this point, you are not discussing the questions in good faith, and I'm done with this conversation.
(And no, I'm not backing off my position.)