I don't think it's that God couldn't create a universe without evil, it's just there's a process for making us good AND retaining our freewill.
So he's letting us help to create a universe without evil...
Evil is necessary in this process, but evil is really just God "occluded" - Satan is in this sense working for and with God in this process of teaching humans about good, hence the line "God works in mysterious ways"... We don't know the process, which is why it's faith-based.
It's like yes, your parents could give you a lifetime of pocket money all at once, but they're not going to because you have to learn patience, self-discipline, and saving up for the things you want (or can afford). You have to make choices in that process to learn about those things.
Humans are temporal... God is not.
So for God, God created a world without evil in which humans have freewill... It's already been done, instantly for God.
But we don't live on the same temporal plain.
Claiming God can't do it, is like being the kid asking for ALL the pocket money at once. Parents could do that, but they're letting time and your own temptation teach you the lessons.
That's part of the mysterious ways. But in faith, outside of time, and with the right beliefs and choices, a world without evil where people in your life still have freewill already exists... It's up to you to live there in it, in time.
...and you may end up living there anyways.