First, Isaiah 53 is a prophesy of Jesus on the cross so that is not telling you anything about His appearance. He has been beaten and bludgeoned so of course there was nothing attractive about Him then.

Even if I were to grant your reading it does not tell me anything about Jesus appearance. It just lets you know He did not physically look like anything special or walk around with a sun on His head.

I agree with your last paragraph but where does the Bible say that? Does it say your heart was black and now your heart is white?