You give a number of problems. But before looking at them, there’s a more important question: Do you have a reason to follow Jesus? If you do, we can talk about the problems, and probably deal with them. But Christianity doesn’t continue because of those kinds of arguments. It exists because people feel they’ve experienced God’s presence, or they find Christianity makes sense of life, or worship and the Christian community is important to them. Is that the case for you?
If so, and you’re just worried about the kinds of issues in the OP, there are two general approaches. The one most common here is to convince you that they’re aren’t any contradictions, it makes perfect sense for God to punish people who reject him forever, etc. Read the other posts. Maybe you’ll find them convincing. I don’t, but most Christians do.
The other approach is to see the Bible as a human witness, something written by people who experienced God’s actions, but were still fallible humans, and who sometimes misunderstood what God wanted. (No, I don’t think God wanted Israel to commit genocide, nor do I think they actually did.) As to the Mafia boss: most Christians, I believe even those participating in CF, think God makes allowances for what people know. The people who end up in trouble are those who consciously reject the Good (as best they know it). There’s simply no way to make a person like that fit into the Kingdom. We can’t talk about it in this particular forum, but if you look in Controversial Christian Theology you’ll find plenty of us who doubt your points 3 and 4, and don’t think Scripture even teaches them.