Jesus is of one substance with myth.  So, is the Father.  They're just interrelated entities in the man-made myths of creation, the totally wrong explanation of our place in the cosmos and fairy tale notions concerning our eventual destination, which are the central topics of concern in virtually all religions.  Just pick your favored brand of superstition, magic tricks and self-delusion.

God the Father, God the Son and God the Holy Spirit are three persons in one. They all have the same substance, essence and nature and are equal, yet one.

I have not studied Greek, and I wish I had.  A knowledge of Greek is almost essential if you are going to be learned in theology.  Of course if you are some sweaty goober Fundamentalist preacher bawling into your microphone in some auditorium masking as a church, you don't care.

This phrase of one substance was hotly debated at the Council of Nicaea in 325.  The difference was between the  terms homoousios and homoiousios. The word homoousios means "same substance", whereas the word homoiousious means "similar substance". Note the difference of the "i" or iota in Greek.  That tiny difference was huge. The subtle Greek language was ideal for theology and this is why so many heresies and sects arose in the East.

The Council of Nicaea was convened, in large part to solve the dispute between the Arians and the orthodox.  The Arians believed that Christ was a creation and not God.  The orthodox believed in homoousios, that the Father and the Son, were of one substance, to wit: God.  The homoiousios crowd, the ones who wanted to insert the "i" was the compromise position.

Some historians believe that the Emperor Constantine, who presided at the Council, threw his weight to the homoousios faction and put them over the top.

The Fathers of the Council had scruples about homoousios as it could not be directly found in the scriptures but had to be deduced from philosophy about the workings of the Trinity.

So, my children, if you believe in the Trinity, then you subscribe to homoousios and you can evidently thank the Emperor Constantine!

From the book The Crucifixion: The compassion and love that was Jesus comes through clearly
when we learn that we do not need to seek forgiveness, for we are not condemned; we do not need
to be saved, for we can never be lost; we do not need to seek eternal life, for that is what we are.
The truth is there is only One Being and we are all part of it.

Yes, even though this is difficult for our human minds to grasp on to. The Father and Son (Jesus) always were and will be. The Son is God who came as as a man to die for our sins. Look at it this way. There was a time when we will call for this comments sake "God's time" when God spoke to man like in the Old Testament. Then there was a time when the Son (Jesus) spoke to man which was the 33 years he walked on the earth. We are now living in the days of the Spirit, Jesus said he would send a comforter (the Holy Spirit). All 3 are God, but all 3 serve a different role. There is only one God but to fully understand him you must be him.

Well,I can't comment on this with a huge degree of certainty as far as what the truth would be, but I will say that, from a historical perspective, regardless of what side you chose, you would probably catch a beating if you happened to be in the wrong place at the wrong time during the fierce war between the followers of Arius and the followers of Athanasius early in the 4th century. An ancient debate that still goes on today amongst various sects.

Yes, and, that's final. Read Genesis 1 and then read John 1.

Although Jesus is not the Father, yes. He is one Being with the Father, because there is only one God.