When even a ghost that can't talk feels REAL, you know it's a good novel. Just the way the author describes its actions and facial expressions... really surprised me for a web novel especially.
Also, the MC being reincarnated actually works well in this story as his educated and modern thinking helps him.
So the MC starts out as a relatively average and normal person, but suddenly becomes:
1) master tactician
2) master fighter
3) master alchemist
4) master engineer
5) master creature creator?
Even though we are in a futuristic setting, it still feels like modern day or earlier.
Even though we are spread out across the Milky Way and other galaxies, it feels smaller than the Earth.
The whole novel is plot armor galore.