Why Satan?

I have come to see the Bible as a book of myths, but I still think about some of the principles and teachings and I try to makes sense of them. It's probably because there are some questions I have had and some things that have bothered me, that when I asked were always explained away with apologetics. Now I am asking. 

One concept I have always struggled with is that of Satan. 

To me, Satan doesn't make sense. I understand the whole idea of balance and of light and dark and good and evil. I get that. And it stands to reason that in a big fantastic story the hero must have an enemy to conquer. I'm a writer of fiction (sometimes). I know how this works. 

But, here is my problem with the premise of Satan. My problem is that it's problematic and contradictory for a lot of reasons. 

Let's take for example this narrative that God is all powerful, all seeing, all knowing and all wise. We are taught about God that nothing happens that isn't according to his plan. We are taught that God IS LOVE. That God is a loving God who created us all in his image and likeness. 

That brings me to two questions. The first being, wouldn't that mean God created evil on purpose? And second question is, are we sure it's actually Satan that's the evil one in this story?

The first point on God creating evil on purpose. If God is all powerful, why even allow Satan to exist? For fun? To have something to compete with over the souls of humans, God's supposed best creation of which he loves so dearly? 

If God created everything than God created evil and Satan. And if God created this evil and knew how everything was going to play out, why did he always act so perplexed by everything and why did he need to intervene at all? It doesn't make logical sense. Also, If God created Satan as a part of the big divine plan then that would just mean Satan was another thing working for God, to fulfill some weird ass prophecy. Like, if Satan is weeding out the bad apples for God, wouldn't that mean Satan was doing the right thing by God? 

And if God didn't create Satan than who did? Where did he come from? If Satan exists and the creator of everything didn't manifest it then that means God is not all powerful.

The other part is the idea of God being all loving. God of the Bible is loving in the way a toxic boyfriend is loving. You know, with things like, "I hurt you for your own good," and, "Why'd you make me do that to you?" If God created us knowing we were going to "fall from grace" and knowing he was going to have to pull off a weird loophole where he sacrificed himself to himself to save us from the rules HE MADE, doesn't that mean he really kind of sucks at his job? When I think about it, it kind of looks like God is the evil one and Satan is just doing what he's told. Which is weird. 

Satan doesn't need to exist. Hell doesn't need to exist. If God is all powerful and actually loves everyone then there is no reason for either of these things to exist. The idea that God and Satan are in a tug of war over the soul of humans it disturbing to say the least. And it doesn't align with what the main narratives are. If Satan can challenge and possibly defeat God then that means God is not all powerful. If Satan can warp God's plan under his nose then that means God is not all knowing. See how this falls apart?

You're telling me that God is going to create a world where evil exists from which only he can save us, but in order to be saved we have to use an archaic book from the bronze age to try and piece things together and follow a bunch of arbitrary rules while an evil being tries to fool us. We are supposed to fall on our knees in worship without actual evidence and if we don't or can't or were born in the wrong place he's just going to send us to hell to suffer for eternity? 

That's not love. That whole "God's grace" thing is gross. YOU MADE THE RULES, GENIUS! I stand by my assessment that the God of the Bible is a tyrant and an egomaniac. Why would I want to worship that?