The end was ...fine. Not too bad. Rushed, but it didn't feel too awful as the story lacked something midgame ....was it clarity? It became very political, which was its thing. It tried to portray different political situations of nations and how they are pitted against each other. I believe the hiatus in between the releases of the chapters (at least here on mangadex, don't know about Japan) broke the story's neck, though. Too much stuff was going on behind the scenes, too many characters have been introduced and you simply couldn't remember all of their names or even their existence later, if they appeared in like two chapters and then there is a release gap of 3 months in between new chapters. Sometimes it even has been 5 months, if I remember correctly. Those breaks in between and the story's complexity just didn't work.
Though the last few chapters felt like the complexity has been strongly reduced, which was the best thing the author could do in my opinion, as for the above given reason. (It didn't work out.) Also the release schedule stabilized to one release around every month. One could finally catch up to the story once again with ease. Well, the reduction of complexity seems to be a byproduct of the story being rushed to an end. The only regret in this hindsight is, that on that level of complexity the story could have run a few chapters longer and be rather enjoyable. We also could have had seen more closure to the characters. E.g. get MC and MLI (village girl) together, see how the princess ascends to the throne and how the city develops (maybe how a international railways are being build). We also could have seen, how the side characters are married off into a happy end too and all that kind of feel-good stuff. But if the cleanup at the end was strongly bound to the rushed end, I welcome both.
The MC's nature of being isekaied and OP was just a setup, like many stories do. It allowed the story to ride on the isekai hype and let the author have a MC, that can do crazy shit, when he needed to do something differently or wanted a quicker, more direct solution to a dilemma of the story. In that way MC actually is a cheat character, alright.