The main character isn't a character, he's an obsession with knowledge given flesh. Supposedly his character motivation is a desire to have the modern amenities of his prior life in this new one, yet he never actually savours any advancements made, instead the narrative is single-mindedly focused on knowledge. Knowledge is so great... and books! He loves books. Not the emotions stories bring, or the advancements the knowledge can provide, just a strange perverted focus on the concept itself.
And you know what? Maybe that'd be enough if the author themself had an interest in knowledge and sharing it with the world, but that isn't what's presented here. Instead it's just a tool to show how cool and smart our MC is. You know what his first major advancement is? Using aloe topically for skin and wound care. You know, the thing that we have written records of doing older than the Pyramids because it's such common sense. But apparently no one in this world has recognized this, as the villagers treat this alone as revolutionary enough it will completely upend the village. And ok, maybe we could suspend disbelief... this is a different world and historically their humanity has seemingly gone through multiple civilization-ending events, so maybe that bit of knowledge just got lost somewhere... Except the MC literally says the whole reason he could identify it is because he read about it in a book of wild herbs with medicinal use from this world! Not even from the book from an ancient civilization, a regular one!
Just awful. It's a power fantasy where knowledge is power, but not because the knowledge he has is revolutionary, it's just that this world is an inconsistent backwater that only exists to make him seem more impressive so people will clap him tying his shoelaces together.
Also the series is setting him up with the village chief's daughter who is an actual child while he is very clearly a middle-aged man and his new body has not affected his mental state whatsoever. Japan, please, stop putting this in Isekai.