The protagonist has apparently reincarnated multiple times and is still 17 years old. Having defeated a demon lord and a demon god, it's obvious they should have a lot of experience and strategies. I expected them to be strong once their attitude changed. I read a manga with a good story because...
Why is this style bad? I actually prefer it when the main character suffers a bit and has some psychological depth. It's like in anime, it's more intense because it seems like they're traumatized and they're the ones who help themselves to become stronger.