I'm still on the fence if the author is solid or not, but the form of the ghost is fascinating.
The world/soul of the ghost/hero was and is a beautiful field of flowers, but it's actual form, the headless grudge, the cold resolution to exterminte demons in the previous chapter, and the trauma seem to be challenging the values of someone who was and still could be a messiah.
Taking that into consideration, it's interesting that his ego/heart seem to be in conflict. There's the conscious desire to return the body and be done. And then there's the impulse/heart's desire to be a hero and save others. Despite the current world objectively being underprepared for the demon invasions, the former messiah hero is not consciously acting on his instincts anymore to try saving the world.
I wonder if the mangaka/author is improving or consciously aware of how interesting their set up is. They do frequently slide into tropey territory, but the pieces for something cool are legitimately there...