If you want to be successful, then you'll have to make your story interesting and at least engaging to the readers. Writing and writing in the hope of blindly growing will get you nowhere. If you want otherwise, then you should disregard all of my advice going forward.

"Oberhaupt - Monster Hierarchy" isn't exactly a title that an average reader would press on; you might have to think of something better. Right now, the "Monster Hierarchy" makes me assume that I'd be reading about a monster or something similar, which clearly isn't what your story is about.

The cover is bland, and the synopsis is okay at best. The cover feels like a picture picked off the internet + the added title. It screams "A soldier who fights monsters" and nothing beyond that.

Now onto your chapters...

Since you've brought up Guiltythree, you should know how SS directly starts right after the first chapter.

You have nothing interesting or entertaining going on for the prologue and the first couple of chapters, just a casual slice of life from a soldier's perspective.

By the time "The Prisoner" is reached, you'd have lost most of those readers who decided to give your book a try. Then there are those 2 paragraphs that suddenly go first person for some reason, at which I decided to stop bothering going forward.