I"ve thought about it a little more and I think I've nailed down the core problem with this manga. The author starts with an idea that is good in theory but seemingly puts no thought into how that idea works and they fail at even the most basics of writing. Here are a few examples.
THE SPIRIT
I mentioned it in a previous comment but the problem with the spirit is it's actions seem arbitrary. We can tell it's sentient as it specifically punished the one noble girl by turning her into a skeleton until she repented earnestly. The problem is the spirit's status as a plot device is too transparent. It only acts when the author wants it to which isn't even that often. This creates a core problem in that the series lacks any real WEIGHT to it. Nothing matters and no crisis has any real value because the spirit could solve it all in an instant in theory. Kill the leader of Secondaria, turn all the supporters of deforestation into vampires, ect. Because there are no established rules or logic to it's actions it COULD do seemingly anything at anytime. It would be like if in Harry Potter he had a magical guardian spirit that could one shot voldemort if it felt like it. The series would lose all tension because the main villain is only a threat if the author allows him to be and this fact is so transparent that no action feels like it truly matters.
THE VAMPIRES
The vampires represent another rather large issue. Namely the author connects ideas together that are incompatable. The vampires are introduced as monsters attacking people only to turn out they are the victims. So far so good it's a tried and true plot twist. But the problem is that because the author doesn't want readers to see the vampires negatively their attacks are justified in every possible way. They attack humans because they chased off the wolves they feed one. They don't kill humans, they just drink a little and the human dies of fright. NOTHING about this explanation makes sense. If vampires can feed on any blood why not raise livestock? Even wolves can technically be tammed to some degree if you train them right. In fact why not cows they have more blood! Then they could sell the milk to humans to make money. Or alternately why not make money and pay humans to let them have blood? Plenty of poor people would jump at that chance. On another note PEOPLE DON'T DIE OF FRIGHT THAT EASILY! Unless everyone in this world has a damn heart condition they shouldn't be dying of fright so often that it's considered a fact they murder their victims. The author thought only of making the vampires misunderstood victims and not how to make the idea actually work.
SHEER LACK OF EFFORT AND CREATIVITY IN REGARDS RO RACES
To be clear it's not like the author's choice in races are bad individually. The problem is the extremely limited and unimaginative scope of races as well as the lack of effort the author takes to justify this limitation. For example humans and elves are fine. But then why no dwarves? Why no dryads or orcs or goblins? It's not that they HAVE to have those but it's a noticable gap when you include some fantasy staples and not others. The bigger issue is the vampires, mummies, and skeletons. All three are traditionally undead races and yet none of them are treated as such. They are all treated as if they are simply born that way and as alive as anyone else. This is extra confusing for the mummies as they can look 100% human and simply choose not to and simply live outside without shelter (which again the spirit does nothing about). It would be fine if only PARTS of a mummy looked human with them overall either being undead or monsterous under their bandages. But no it's 100% because the author needed a waifu mummy heroine. So the author sets up a world with races that should clearly be undead ... but makes no effort to explain why they are not. Sure maybe we can excuse the vampires since many manga don't bother to treat them as undead already. But the other two needed SOMETHING. This clear lack of explanation for ANY of the races in this series makes the overall read feel cheap like "If the author doesn't care enough to explain why should I care about any of this?".
THE DEFORESTATION
The last issue I want to bring up is the deforestation effort of the Secondaria alliance. It's not like the idea of a merchant alliance persuing profits over the greater good is strange. The problem is that is not what they are doing. They are threatening war, rejecting trade deals, even ignoring the greatest revolution in transport and communication their world has ever seen! All for the sake of cutting down trees for some vague development effort that doesn't even have a solid purpose or end point. These ARE NOT merchants! A real merchant would be tripping over themselves to make deals with the vampires to get their own carrier service started. Sure I guess you could argue they are just racist to the point of refusing it, but that is in contrast with the idea they are corrupt merchants looking only for profits at the expense of everything else. Meaning all were are left with is a bunch of jerks who are racist because they just are, who want to destroy the forest because they just want to watch the world burn. Again this conflict between being after profits and yet ignoring every single profitable venture the MC creates in favor of a self destructive plan just DOES NOT WORK!