Smarter people than we have wrestled with that question since ancient Greece, if not before. (It's generally referred to as the Problem of Evil.)

I don't accept the usual explanation that the Lord works in mysterious ways (or various similar wording). To me it's an evasion, a non-answer. I get the impression you feel the same way. Without getting into the metaphysics of it all - please just know you're far from the only one who feels as you do. The general presumption in our society is "Well of course there's a Higher Power, you just [don't understand / won't understand / can't see it, etc]." IOW, it's *your* problem if you don't grasp or can't accept what "everybody knows."

That ain't so. I can't address much of what you wrote. I just wanted you to know that you aren't alone in feeling as you do. Far from it.