An Existential Meltdown

I grew up with the notion that God and his angels started off all happy up in heaven, and then one day one angel decided he was as good as God and ruined everything. He chose to go against God and evil was born. He was banished to hell, along with anyone who followed him. From then on there were the Trinity and the good angels in heaven, and Lucifer became "the devil," or Satan, and had all his fallen angels, also known as demons, with him in hell.

Hmm. I'm thinking that's not really how it all went down, but the more I study the more confused I get.

It seems that the name "Lucifer" is the Latin translation of "Morning Star" or "Day star" referenced in Isaiah 14:12 which is a taunt directed to the king of Babylon. (Read Isaiah 14.)

But then this same term is used in 2 Peter 1:19: "And we have the word of the prophets made more certain, and you will do well to pay attention to it, as to a light shining in a dark place, until the day dawns and the morning star rises in your hearts."

And again in Revelation 22:16 : "I, Jesus, have sent my angel to give you this testimony for the churches. I am the Root and the Offspring of David, and the bright Morning Star."

So Jesus claims to be the Morning Star, which in Latin is Lucifer? That's confusing.

Also, I always blamed evil on Satan (Lucifer). He was the one who became evil and now taunts humans and causes all kinds of evil in the world, right? But John 1:1-3 says: "In the beginning was the Word, and the Word was with God, and the Word was God. He was with God in the beginning.
Through him all things were made; without him nothing was made that has been made."

So, nothing that has ever been made was made apart from God, including sin and evil?
Maybe someone who has more knowledge can shed more light on this for me.

And what about Beelzebub (aka Ba'al Zebûb, Lord of Things That Fly, Lord of the Flies), the deity that was being worshiped and was called "the prince of demons" by the Pharisees in Matthew 12:24: "But when the Pharisees heard this, they said, "It is only by Beelzebub, the prince of demons, that this fellow drives out demons."

Why do we assume these are all the same-- the serpant, Satan, the Morning Star or Day Star or Lucifer, Beelzebub?

I know so little. Maybe none of it matters. Maybe it matters a lot. I don't know. But can I blame the origins of evil on "the enemy" or was it just God's plan all along that it would exist? I'm not sure. But it does exist. I believe that God is the victor and in Him I will be too. I believe that God loves us all very much and we are to love like Him. But it's all very confusing to me right now...