Thank you for the question. It is a tricky question because it suggests that God is unfair in the way he deals with us and to a certain extent this is true but not in the way you think.
When God created the world, he made human beings with the will and ability to obey him, and also to disobey him. So it is not that God made us to sin. He actually made us so that we can have a joyful and obedient relationship with him. But as we choose to go against God’s will, we sin and we break off our relationship with God. I think this is not hard to see in our everyday lives too. As we come to our decision making, we are often faced with the choice between doing the right thing and doing the wrong thing. Unfortunately, often we choose to do what we want to do instead of obeying God. So we do make deliberate choice to go against God.
Since God is just in His character, He can’t let our sin unpunished. So the just thing for God to do is to punish us. But since God loves us, he planned to save some even before the world was created. His plan was to send Jesus Christ to die in our place, to take the punishment for us. Since He is all-knowing, He knew exactly who He wanted to save. He does not have to do this but he chooses to because of his kindness towards us. So that’s why you will find that the Bible does not talk about who God pre-destined not to save, because all of us deserve not to be saved. But out of his generosity, he chose to save some.
Therefore, it is just for God to punish us, since we choose to sin against Him by our own choice. But it is a surprising generosity that God chooses to save some.
Now it may seem unfair that God saves some but not others but we need to remember that God is God! He made the world and owns it. He and he alone has the right to do with it as he wills. We have not right to tell him what to do. The amazing thing is, though, that rather than being an aloof God who does not care, he is a loving God who has done everything possible to save those he has chosen to save. However he has not told us who and he has not told us why and while we may wonder about this, we cannot tell him he is wrong in doing what he has done.
To answer your second question, the Bible upholds that God is the creator of all things, including things on earth and things in heaven. This includes heavenly beings, like the angels mentioned in the Bible. Satan is understood to be a fallen angel who, like humans, makes deliberate choices to disobey God. The greatest power Satan has is to lie to us things about God. As we listen to his lies, we sin against God and suffer the due punishment. That means we cannot really blame God for putting Satan here since we can choose not to listen to what Satan says. At the same time, because of Jesus’ death for us, when we put our trust in his death for us, we will no longer suffer any punishment. So the power of Satan is disabled and we no longer need to fear him.
As you can see in the answers of both questions, the centre of all things is about what Jesus has done for us. It’s important to trust him and know his impact in our lives.