@Elmithian Well, there are also a bunch of little things that bother me, such as the fact we know what happened in her first and last lives, and we know some of the ways she died, but that's it. We don't know about what happened in those lives, what the heroes of those lives did, what the goddess did/didn't do during them, and I, personally, am still bothered by that creature/thing they saw that was trapped in the castle, it shows it and talks about it but it doesn't tell us what it is exactly. It just says that it's related to the nobles and the king that threw the FMC to the commoners to kill. I assumed it was a chimera of them fused together in eternal pain and torment or maybe, some kind of looped time spell that is just them dieing to the demon king over and over, but since it doesn't explain it bothers me.
From what we know the conclusion we'd most likely draw is that the goddess is either a bitch who enjoyed watching the FMC reincarnate, suffer, and die over and over, or she just didn't do her job well at all. Now, that doesn't mean that those couldn't be true, but without the full story we can't come to a definite answer, only guesses and assumptions. I think she might've just been half-assing her job, and by the time she realized the world was about to collapse, the FMC already died over and over and over.