Here are several ideas to consider:
1. Significant difficulties and challenges facilitate one’s ability to fully turn towards Hashem. When pushed to the wall with no where else to turn comes an opportunity. Ultimately, if we take that opportunity, we are rewarded and what seemed bad is in essence very good for us. Turning to Hashem includes both the recognition there is absolutely “No one but Him”, as well as the turning to Him in Tefillah.
At an Agudah convention years ago there was a Q&A session where someone asked why Hashem brought the Holocaust.
2. One Gadol (I don’t recall the names) answered that before the holocaust the enlightenment movement (and reform in America) were raging across the Jewish communities. The holocaust was therefore not only a punishment, but it helped facilitate the rebuild of the (frum) Jewish people across the world. (To an extent anyone from that generation would find unbelievable).
Another Gadol did not like that answer and said something to argue with the first Gadol. However, what he said is also a great answer to the OPs question.
3. He started going through each of the stories of the 10 sages killed by the Romans, one story at a time until he finished all ten. Then he asked “why were these ten sages who lived over 100s of years killed? Because the brothers sold Yosef.
Ten sages who lived over a period of 100s of years thousands of years after the sale of Yosef Hatzadik were killed as a kapparah.”
To assume we can know why something has happened would be foolish on our part, even if the reason seems obvious. We are not above time like Hashem, and there is a larger picture we cannot see.
This can be understood even without getting into the more complicated gilgulim component.
The UN general secretary said these events “did not happen in vacuum”. Those words are a very accurate portrayal of what’s going on (obviously not in the way he intended it). Events do not happen in a vacuum.
The first two points mentioned are very similar.
I listed them both because I think there may be a very important distinction (although I am not sure this is true). In the first, we have an opportunity to turn to Hashem through bechira due to difficulties. In the second, it could be Hashem directing the world, causing a rebirth of klal Yisroel, that may be happening without our bechira- of course for good.
May the geulah come soon.