Question

Hello Rabbi!
For quite a long time, a very difficult question has been bothering me, and every answer people give me feels beside the point.
I'll say my understanding in general terms:
I found the issue of the “problem of evil” in the world very hard. How can there be so much evil in the world if God is wholly good? The answer, “You don't know the calculations of Heaven,” sounds evasive to me, because for example in the events of the last war or the Holocaust, there were horrors that are impossible to imagine or to accept as good in any sense. In addition, saying that everything is part of a good plan raises a question in itself: if God is omnipotent, why, in order to reach the good, do we have to go through horrors such as even children dying? After all, omnipotent means that He could also bring about the good without the bad part…
The answer to this question that actually made a tiny bit of sense to me was specifically Maimonides' words in the Guide for the Perplexed, according to which a person has free choice to choose good and evil, and therefore the evil in the world is either because of the freedom a person has or because of the laws of nature that simply exist, and in the natural order things can happen that are not good.
But my question is this:
If that is indeed the case, then surely one of the explanations of prayer is that it is a request. Aside from the fact that prayer is primarily connection to the Holy One, blessed be He, it is of course also a request. We see many times in the words of the Sages that they prayed and received what they asked for. This is difficult for me first of all because many times I make the maximum effort on my part and pray, and still I am not answered. But beyond that, if the Holy One, blessed be He, does not intervene in the world, how can I ask Him to fulfill a specific request for me? I am essentially asking Him to intervene in the world! And if He does intervene in the world through prayer, then how could things like the Holocaust, for example, have happened? Surely people then prayed with all their spirit and strength, and still there were five years of horrors…
In addition, if God is omnipotent, that means He can also make free choice exist without there being evil, right? After all, omnipotent means truly omnipotent, even if it sounds bizarre to us to the point of impossibility, so a world in which there is free choice without evil should still be conceivable. And saying that He created the world in the most perfect way possible (so that terrible disasters are part of the good) is an evasive answer, because He can create a perfect world without evil, because again, He is omnipotent…
I am very confused, Rabbi; I would be glad if the Rabbi could answer me.
Thank you very much!