The fact that Jesus claimed to be God and the Savior of the World is nothing more than a claim on its own. Jesus here appeals to the additional corroborating evidence that support His claims.
Others, like John the Baptist, agree with the Gospel of Jesus and proclaim the truth of His message. For 2,000 years people have testified to that claim, and changed lives and personal experiences by the millions have to account for something. But, Jesus also does not point to this evidence as His ultimate proof.
God’s Word is another exhibit. Thousands of years of revelation became clear in the life of Jesus. Prophecies were fulfilled and complicated writings became clear once the crucifixion and resurrection occurred. But that too is not the ultimate proof. Jesus even points out how diligently the Jewish leaders studied scripture and still miss the point. Nothing is more dangerous than reading with the intent to confirm preconceptions.
Jesus’, ultimate confirmation comes from the Father. The works Jesus is able to do, combined with all the testimony of believers and Scripture are what confirm who Jesus claimed to be.