So, you’ve actually raised three subtly different points:
1.) Bad things can happen from Good things.
2.) If free will exists, there needs to be inperfection.
3.) You need temptation and the possibly of sin to be saved.
So let’s presume that’s all true - we should presume that the universe does all of that perfectly without introducing any unnecessary suffering. Let’s take a couple of specific examples:
Loa Loa filariasis is a type of endemic parasite that lives in people’s eyes and makes them go blind, this has little to do with free will, as it’s not related to anyone’s actions. Given that it affects millions, the overall harm and suffering it presents to individuals over the centuries doesn’t appear to be commensurate to any of the positives that can be gained over eyesight loss being, say, temporary. No?
Likewise, Volcanoes - they largely just kill people who live nearby indiscriminately, while a few hero stories of people who made it out are nice: there’s not a great deal of Good that can come out an obliterated town.
Likewise Paedophilia. While people need to have free will in this Godly universe, there’s no necessity in any scenario for human adults to be sexually attracted children to the extent that they are driven to rape and murder three year olds.
If these three options are the goals: then by all means, jealous, anger, murder, assault: but those at sinful temptations enough, why bother adding drive to rape children to some individuals on top of all that?
1.) So lets have a universe where any bad event, always have multiple individuals in a place or location to render aid or assistance; to allow humans to decide to be good, and allow all suffering to lead to a good outcome through the actions of others. Natural disasters only ever displace people, rendering them reliant on others rather than outright kill them. No pointless suffering for which there’s little objective chance of resolution.
2.) So no child rape and torture - humans kill, mame, and can still sin, no problems!
3.) The possibility of sin and free will are still there, just pointless suffering is removed.
The issue with Felix Culpa is that it’s a naive excuse and dismissive non explanation for the state of the world; in reality, humans could design better scenarios and situations.