Um, ackchually, there is one manga that has pretty much exactly that character. Forgot if it was a true isekai or just your average game world type setting, but that usually doesn't matter. It's one of the betrayal mangas anyway.
Best instance of that I have ever seen is how not to summon a demon lord, the guy acted like a total thug, looked like a orc, was a prime minister, and one of the the main girl was forced to be engaged to him which would make him a king. Aside from talking rudely he never did anything bad, was over weight do to being stuck at a desk all day with paperwork and needing large amounts of sugar to help stay awake and alert with the long hours, was against the marriage and didn't want the crown, acted like a thug hoping it would trick others into disliking him and stop the wedding but the queen knew and he couldn't decline her. We saw him working diligently many chapters, but all just assumed it was because he was exited to get the crown, the quite in the comment section when he proved to just be a good guy and that we had all profiled him was brutal.