"In 19:10 This being tells others that, He too relies on the...

"In 19:10 This being tells others that, He too relies on the testimony of Jesus. So It can't be Jesus. Then in 19:13 we are told His name is the Word of God.

"The being" as you put it, is NOT the one named the word of God.

And I fell at his feet to worship him. And he said unto me, See thou do it not: I am thy fellowservant, and of thy brethren that have the testimony of Jesus: worship God: for the testimony of Jesus is the spirit of prophecy.
And I fell <- This one is the one that -> And I saw heaven opened, and behold a white horse; and he that sat upon him was called Faithful and True, and in righteousness he doth judge and make war.
His eyes were as a flame of fire, and on his head were many crowns; and he had a name written, that no man knew, but he himself.
And he was clothed with a vesture dipped in blood: and his name is called The Word of God.
And the armies which were in heaven followed him upon white horses, clothed in fine linen, white and clean.
And out of his mouth goeth a sharp sword, that with it he should smite the nations: and he shall rule them with a rod of iron: and he treadeth the winepress of the fierceness and wrath of Almighty God.

Acts 17:31 - because He has appointed a day on which He will judge the world in righteousness by the Man whom He has ordained. He has given assurance of this to all by raising Him from the dead.

The subject of why the name is not known, is another subject, as the name is there, so it obviously has another meaning WHY it's not known.