It starts generic for the first several chapters, the sort of thing you're already bracing yourself for it to go rapidly downhill.
...But then it really starts getting its legs under it after a bit—I'd say, around the arc he first gets pulled into an architecture project instead of "generic adventuring with abuse of crafting skills"—and inexplicably it just keeps getting better after that.
Once it gets going, it has solid and compelling character writing (this is very much a series about the lives of the people in it, rather than just the adventure itself), thoughtful segments on the ventures in fantasy architecture and engineering, serious consideration given to characters' life choices... You eventually get the feeling the author and artist together could just as easily have written a compelling slice of life manga about kids at university or something. Though I prefer this.
Also: Mad props to the translator of most of this. I don't normally take well to liberally-translated stuff that chooses to try to match tone across language at the expense of literal meaning—especially, for instance, in all the jokes. But the TL is a funny person and also pretty darn good at making dialogue sound natural, and for this, it really, really works.
Anyway, this is truly lovely.
This manga currently has an 8.54 rating so I decided to read it out of curiosity since I like fantasy stories.
…. Why? Does it get better much further in or something?
FWIW, chapter
23 is the specific point where I stopped and went "wait, what the hell, this is not just pleasantly readable junk-food, which is what I started out reading, but actually good now. When and how did this happen?"
Although I'm fairly certain that just skipping to that point wouldn't give much impact; the character-building leading up to it is what made that chapter work. Nor is it some sort of series-making, mind-blowing chapter or anything like that in the first place. But it is what I'd put down as a watermark of "if you've come this far and don't like what you've seen, it probably isn't your series, and if it is your series, you will likely know it by the time you're here". (No one should really be expected to read a big chunk of chapters just to see if they eventually like something, but you did ask, so!)
For completeness' sake: It's not some sort of transcendent masterpiece of fine literature. But it did pass the bar of "immensely better than I first expected, endearing, and enjoyable" for me. Something-something "perfect is the enemy of good".