Hey Reply. I’m a little late to the party, but I have some thoughts for you. I assume you’re still lurking on your own thread.
With all due respect, I think you’re approaching the question from the wrong angle. I should disclose up front that I’m an atheist (some would call me a strong agnostic, since I don’t claim to be able to prove God doesn’t exist), but I know many intelligent, thinking Christians and the way they come to that belief is rather different from the path laid out in your OP.
Let’s start with the NT. Where did it come from? Mainstream Bible scholarship is that there was this fellow Joshua who did some remarkable things. After he was crucified, some of his followers continued to spread the Good News of his ministry, passing along by word of mouth his teachings and stories about his life. This process continued for many decades, at which point the canonical Gospels were written down. Were they divinely inspired, in the sense of being more-or-less dictated by God? Few Bible scholars I’ve read think so. Rather, this was just ordinary men doing their best to preserve a remarkable story. Doesn’t mean the story didn’t happen. The Revolutionary War happened, even though all the accounts of it were written by ordinary men.
Move next to the interplay between NT and OT. Many of the issues you identify bother me also, but they’re side issues. Understand that the OT is also just a human compilation of teachings and stories passed along by word of mouth, only in this case the period of oral transmission was centuries rather than decades. Even when I was a Christian, I didn’t think the OT told us much about God. Rather, it tells us a lot about the people who transmitted and eventually wrote down the stories. (Ken Davis’ Who Wrote The Bible is particularly good on this topic.) Anyhoo, the nexus between NT and OT is simple. A major tenet of Christianity is that Joshua and his ministry fulfilled various prophesies in the OT. Personally, I think a lot of the prophesies are strained and I’m suspicious that some of the fulfillments (perhaps all) are mere storytelling, but that’s the connection.
The question of whether to become a Christian, then, is simply a matter of whether you think Joshua was the Son of God and was crucified for our sins. The NT story doesn’t need to be accurate in every respect for that to be true. Indeed, many Bible scholars (though not most) don’t even accept the physical resurrection. (Doesn’t appear in the earliest extant copies of Mark.) Theologically, a spiritual resurrection is plenty good enough. Nor, IMHO, do the array of issues since interjected by apologists and skeptics matter much. The cosmological proof satisfies those who want to believe and doesn’t those who don’t. It’s a side issue. Free will and determinism is impossible to resolve. Great minds have struggled with that one for millennia. None of us here are likely to pull it off. In the meantime, you have to make a decision.
In closing, I’m going to interject three issues (on which others are of course welcome to comment) which explain why I come out the other way. YMMV. First, what reason do we have to believe the NT story is true? Stated a little differently, what’s the difference (if any) between Christian faith, on the one hand, and Muslim faith, Hindu faith, Buddhist faith (not a religion in the Western sense, but fills the same niche), Chinese ancestor-worship faith (ditto), Mormon faith, Hellenic faith, etc. on the other. Second, by what power or principle was God required to sacrifice his only Son to extend grace to the world. I understand the conceptual need for grace - have issues with it, but understand - it’s the sacrifice that baffles me. I mean, he’s God. To whom is He sacrificing his Son? Himself? And let’s remember the Trinity, so God is actually sacrificing a part of Himself to another part of Himself and accepting that as vicarious atonement for mankind’s sins. That makes my brain hurt. Third, why would God make belief in a story the touchstone of grace, as opposed to, say, striving honestly in one’s heart to live by His commandments to the extent of one’s ability. (Being God, he’d know the truth of it, not just what you proclaim to your fellow sinners.) Thing is, I can see how belief in the story was important to the religion’s founders. Without belief, they’d have been out of business. But strikes me as a very un-Godlike was to go about dispensing salvation.
Goodness knows there’s lots more to this topic. But that’s my two cents worth.