Christians need to understand that merely proving that Jesus was crucified and resurrected does not prove that mainstream Christianity is true by default, as Biblical Unitarianism remains an option.
Whether Jesus claimed he was God clearly (yes, I had to emphasize that) remains a considerable obstacle for many people. To see far-fetched interpretations of Jesus’ words reported in the gospels as entailing that he claimed divinity is intellectually indigestible for many. I always used to say to myself, “Why is Jesus playing this game of charades?! Why not just communicate clearly?”
A response (not the only response) I typically get from Christians is that I should not be so “arrogant” to demand that God “reveals Himself” in a manner I “expect” Him to, but to be “humble” enough to accept the way He has chosen for Himself.
But I never “demanded” that God chooses a “specific manner” of communication, just that He does not confuse us with such vague speech and unambiguously tells us what we are to believe when it comes to the most important article of faith (i.e., identifying the correct identity of God!).
You could take whatever issue you want with the Qur’an, but no one could ever deny that Allah is claiming to be God. Unfortunately, the same cannot be said for Jesus when he speaks in the gospels. If I need to learn advanced koine Greek and be an expert in trini/unitarian polemical exchanges and consult countless Biblical commentaries, only in order to think that it is more probable that Jesus’ words should be interpreted as him claiming to be God, well then, we have a serious problem.
Perhaps, Christianity is not the universal religion it is cut out to be?
We also believe in something which is unsolvable and unexplainable. We believe in qadr and freewill. Our minds are limited and can't understand how free will and qadr are compatible according to ahlu sunnah so why can't Christians say the same about the trinity?