That's a very evil-focused thought exercise.
The concept of evil introduces a moral absolute, otherwise nothing could be considered evil. Morals aren't physical, they are not tangible, where do they come from? Humanism/materialism/Atheism can't resolve this.
Can you confirm God is not willing, does not, or cannot prevent evil? The world could be a much worse place, there is really no barometer for how bad life could really be. The reverse of this thought experiment is God should control everything, which would include
everyone. Would it make more sense if God were a puppetmaster, and we were simply automatons in a perfect world? That would be a very unsettling kind of god. Humans have free will, and are sinful by nature.
Does 'evil' exist, or is 'evil' the absence of good? Would you say the hole in a doughnut exists, or is it just the absence of doughnut? The same could be said for a shadow and light. Evil is not a thing or a force, it is an absence of good.
Everything created by God is good, evil is just the absence of good. I'm sure most will disagree, but there is logic to this.
Mankind's sinful nature causes that absence of good, the appearance of evil. Mankind has free will, otherwise there would be no reason for us to exist. If we all trusted Jesus as our savior and followed God there would be much more good.