Honestly, this is one of those novels that hook you at the start then show how even a great start and great idea can turn into absolute garbage after a little while if the author sucks at making good choices.
A lot of people will probably be tricked into reading this novel after reading the manga, which ends at v3 which is when this story truly takes a turn for the worse after the first big arc, the manga makes for a much better read because it's fast to read, you don't have time to get annoyed nor does the flaws stand out as much and you can quickly read through the bad parts.
In the novel, however, we find that the protagonist is a truly annoying person. He has no motivation to do anything, to do things, he has to be pushed into a corner first where he reluctantly does the bare minimum. He has tons of talent, but never tries to do anything with it except when his life or the life of those he cares is on the line, leading to a ton of issues. His passive stance is frustrating to say the least.
He has no real goals except to "stay out of trouble". Everything he does is forced by outside circumstances instead of by him taking initiative. He has ridiculous power at his hands through a cheat item, but he doesn't use it for anything, rather, he wastes all its power by doing the most useless crap and doing his best to not kill anyone at all, making things even more difficult. Even in war, he doesn't kill anyone until he's truly pushed into a corner, where he cries and vomits all over himself as he kills a few soldiers that are threatening his and others lives.
He's the very definition of a doormat protagonist, his purpose in life is letting everyone walk all over him until they go a bit too far by trampling feces all over his face, in which case he proceeds to beat them up a bit before letting chance decide what happens to them. This trait gets even worse when some girls, which he is too cowardly to be proactive with, ends up forcibly becoming engaged to him because he's too much of a wuss to take that step himself, as he then accepts them both and then gets turned into one of the most henpecked protagonists I've ever seen, he doesn't even get pissed when they, for comedic reasons, refuses to listen to him and thinks he's cheated on them, nah, because instead of getting angry and setting them straight, he just gets frightened half to death. Truly no amount of injustice is too much for him to bear unless they happen to try to attack the girls around him.
Not even some of the worst villains will be killed, not even allowed to commit suicide after trying to kill him and his beloved. Nah, he needs to risk himself to save them while they try to suicide bomb him.
Seriously, just how annoying can you be? It was fine the first 3 volumes because he wasn't quite as involved back then and people expected him to get over himself and face reality, but he never develops mentally.
There's also way too much political strife in this novel, the kind of politics that make no sense in the first place and is just there to create weird, artificial conflict for the protagonist, like nobles targeting him and those close to him over and over again for reasons the author couldn't bother to figure out properly, and I get it, it's difficult to think up a good reason as to why grown adults in a position of power would try to bully kids, steal girls and start wars for no good reason whatsoever, I'd be hard pressed to think up an acceptable reason for such things too, which is why I wouldn't make them do that in the first place unless the situation logically called for some thing similar.
Then we get to the comedy, it's the biggest attraction and focus, especially the first few volumes. It was quite funny the first few volumes, but the author ends up becoming extremely lazy, relying on the same jokes over and over again. The AI's annoyed and sassy quips because he, rightfully so, thinks the protagonist is a scumbag waste of space. The protagonist just complaining about his circumstances. The mc being obsessed by tea. The mc being dense. The mc not being able to handle girls. The mc making random evil monologues when dealing with trash that annoyed him. People reacting to the mc's comments and attitude. It NEVER changes, it's just repeated with different words over and over again, they're beating a dead horse until not only turns to mush but also gets atomized. No joke will keep on being funny if you repeat it dozens or hundreds of times in a short time span.
As the story continues, the conflict just increases more and more, from kids screwing around to nations/countries going into wars and world ending events, with increasingly more depressing circumstances and for some reason the author decides that showing the backgrounds of various side characters was a great idea, wasting tons of time on useless characters no one wants to know about while the protagonist ends up being just another side character in a story made up of just side characters. The comedy, which was the only saving grace, gets less and less focus as conflict and drama takes the forefront with increasingly more cartoonishly evil characters (That often also need to have their reasons and backgrounds explained in sob stories, because no one is evil just because, nah, they're all poor victims, boo-hoo)
This novel isn't worth reading, read the manga instead and stop after that. It's not worth it to continue with the novel where the manga left off.
The author finally managed to make an actually good novel after several ones that sucked in various ways after a while with his newest one, "I'm the evil lord of an intergalactic empire", where he manages to make a protagonist that ISN'T insufferable because that guy, while delusional, isn't a wuss, not minding killing or bringing others down and he's actually strong for real with actual motivation. That one is surprisingly one of the better novels out there, but that just goes to show how much the protagonist's set personality matter. Who wants a doormat justice wannabe nowadays anyway?
Read that one instead, it's simply far superior.