The Son of Man refers to Jesus who was both a man and God.
"Son of man" refers to the prophet Ezekiel.
"Son of man" refers to Jesus.
"Son of man" is ben Adam, or son of Adam, meaning all humanity.
"Son of man" is a prophetic designation.
It means many things, but Jesus used it to identify with us and the prophets. This does not mean that he was declining to be Messiah or only begotten Son of God.
He was all of that.