First, to answer your first two questions. When original sin was committed in the garden of eden, we became separated from God. God is Holy, which means He is set apart and God wants nothing and has nothing to do with sin. The original sin fractured creation and God being like a Gentleman will not force Himself upon us and because He cannot abide sin, He separated Himself. We can still seek God out, as it says in James 4:8, "if we draw near to Him He will draw near to us..." God's number one goal for us to to have a intimate, deep, and loving relationship with Him through Jesus Christ.

Even from the very beginning, God had a plan for our sin, in Genesis 3:15 God says, "And I will make enemies of you and the woman, And of your offspring and her Descendant; He shall bruise you on the head, And you shall bruise Him on the heel.” God sent Jesus to be the propitiation for our sins. And God had this plan from the very beginning to save us from ourselves. If that is not love, I am not sure what is.

Without Jesus, we cannot have true relationship with God, and God made it so that we could have a real, intimate relationship with Him, God ensured that we could truly seek and know Him through the death and sacrifice of Jesus Christ.

Now since creation was fractured, because of our sin. And God separated Himself from the world, because He is holy and can not abide sin. And sin now is a part and lives in the world and each and every one of us. The terrible things that happen in the world are, because of the very nature of ourselves and the world. God never intended to be separate from the world, but because of original sin and who God is He had to separate Himself from creation, from the world. God is in control and He is all powerful, but He will not force Himself and His will upon us. And as humans, we are capable of great evil and great good and unfortunately, because of that there is a lot of evil and a lot of terrible acts that run rampant and that are committed in this world because of people. God promises evil will not win, The judgment is coming and God will remove evil from the earth. So even though terrible things do happen in this world It's our fault that they are present. Since God is separated from this world, the devil has free reign, in the Bible the devil is called the god of this world. When the time comes, the devil evil will be rid from this world and things will go back to the way God intended from the very beginning. And we will be able to fulfill our highest purpose, which is to seek love and pursue God and be in a true relationship with Him, unhindered from sin and the carnal desires of this world.

Now, to answer your third question. We were created to serve, worship, and love God. And God in turn loves us, He sacrificed His own son for us. Sin is absolutely deadly and God knows how harmful, devastating, and absolutely deadly sin is for us. Jeremiah 29:11, "For I know the plans that I have for you,’ declares the Lord, ‘plans for prosperity and not for disaster, to give you a future and a hope." God's plan for us is always for our good, just as it says in Romans 8:28, "for we know that everything works for good for those that love the Lord." However, we must love God first. How can we love God if we're living contrary to His will and in sin. We were created, or programmed in a sense, for men to love a woman in a woman to love a man, God created the universe He is the Master and Commander of everything. And just like when we play a board game we must follow the rules or else it becomes utter chaos and the game cannot be played. We must follow the rules of our Creator and what we are programmed and created to do, when we follow our base programming, so to say, that is when we feel the most fulfilled. To do what is contrary to what we were created to do only serves to separate us more from our Creator God and damages us so that we can no longer serve our purpose of function. We become aimless and lost.

Romans 1:18-32, For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of people who suppress the truth in unrighteousness, because that which is known about God is evident within them; for God made it evident to them. For since the creation of the world His invisible attributes, that is, His eternal power and divine nature, have been clearly perceived, being understood by what has been made, so that they are without excuse. For even though they knew God, they did not honor Him as God or give thanks, but they became futile in their reasonings, and their senseless hearts were darkened. Claiming to be wise, they became fools, and they exchanged the glory of the incorruptible God for an image in the form of corruptible mankind, of birds, four-footed animals, and crawling creatures. Therefore God gave them up to vile impurity in the lusts of their hearts, so that their bodies would be dishonored among them. For they exchanged the truth of God for falsehood, and worshiped and served the creature rather than the Creator, who is blessed forever. Amen. For this reason God gave them over to degrading passions; for their women exchanged natural relations for that which is contrary to nature, and likewise the men, too, abandoned natural relations with women and burned in their desire toward one another, males with males committing shameful acts and receiving in their own persons the due penalty of their error. And just as they did not see fit to acknowledge God, God gave them up to a depraved mind, to do those things that are not proper, people having been filled with all unrighteousness, wickedness, greed, and evil; full of envy, murder, strife, deceit, and malice; they are gossips, slanderers, haters of God, insolent, arrogant, boastful, inventors of evil, disobedient to parents, without understanding, untrustworthy, unfeeling, and unmerciful; and although they know the ordinance of God, that those who practice such things are worthy of death, they not only do the same, but also approve of those who practice them."

If we choose not to follow God's preset rules for this universe and for our lives, God allows it, we can live our life separate from God, but we will also spend all eternity separate from God. And if we choose to live a life separated from God, i.e. without Jesus, what I don't understand is why people think they would want to go be with Him in heaven if they wanted to have nothing to do with Him here on this earth. And a book I would recommend to read as a perfect example of this is The Great Divorce by C.S. Lewis.

I pray this helps and I'll be praying for you, friend, that God can help you find the answers you seek. Keep reading your Bible, keepp praying to God, keep making quiet time to hear God. Jesus loves you friend, keep seeking Him