"I[f] 'son of God' equals God, then aren't Christians making themselves equal with God?"
The clearest expression of Jesus' divinity is not made in the "Son of Man" or "Son of God" sections, but elsewhere.
From his own mouth, he used the great I AM self-referentially, SHOCKING blasphemy to his hearers...unless he was God.
And John begins his Gospel: "In the beginning was the Word, and the Word was with God and the Word was God...and the Word became flesh..."
So, Jesus was the Word made flesh, and the Word is God. Therefore, Jesus is God, the great I AM of Genesis, which is what he called himself in John's Gospel.
Jesus said he was Yahweh. That's as direct a claim of divinity as is possible.