I understand what you're saying but look at it like this. Who created Adam & Eve? Who created their propensity to sin? If I load up a house with natural gas vapors and set a mechanism that ignites a spark when the front door is opened, who is responsible for the house blowing up? Is it the person who opens the door and sets off the igniter or the person who loaded up the house with explosives and created the ignition mechanism? The person who opens the door does so of their own free will ...
Did God create sin? What does Proverbs 16:4 say? Either God created all things or he didn't. He certainly created the environment for it to flourish.
As far as the unbelief argument, it sounds like the work of Jesus on the cross was worthless. If he did indeed pay the penalty for sin, yet God still punishes US for sin, then he's extracting double punishment. But when you're God, I guess you can do that. Either Jesus paid for your sin at the cross or he didn't. If he did, yet you still get sent to hell for unbelief, then there's double punishment. If that's true, how can anyone be assured that their salvation is real since God may not be satisfied with Jesus' payment.
Also, FWIW, the word "accept" is no where in the Bible. No one in the Bible ever "accepted" Christ as their Savior -- that's a relatively modern day invention courtesy of Charles Finney who believed HE could force revival by using emotional appeals. He even gave instructional seminars to other preachers on how to do it. Seems it worked because that's been all the rage since the mid 1800's.