The main issue with this story

This is a standard "middle-aged man suddenly becomes a munchkin" story. I have no issue with that but it employs the common "unwilling hero" trope and that is a really easy way to write a contradictory and annoying character. A few chapters of obliviousness/denial is fine but it's over 40 chapters in and the character has made no progress on his denial/unwillingness. The issue is that he comes off as whiny and his motives aren't consistently established.

We're barely told that he had a traumatic childhood where he witnessed the deaths of many and was saved only as a photo opportunity by greedy hunters. This is supposed to cause him to hate corruption and oppression of the vulnerable but it's only used in passing and isn't well established as a meaningful character trait. I barely remember MC’s trauma in this story. As a result, he comes off as selfish and random. The battles and powerups are interesting enough to keep you reading (7/10). The author was more concerned with creating a munchkin universe (OP bosses and challenges) rather than providing consistent motives for the MC to engage with that universe. As a result, I lose track of whether the main character has decided to be a hero or not and the story drags by introducing interesting-enough bosses that the main character takes entirely too long to decide to fight because it's not his problem...but he'll fight eventually because reasons. It's like when an anime drags on because the characters spend more time talking than fighting. His unwillingness is filler, not character development. Please get to the point.