Yeah, while this story turns other Isekai tropes on their head, it's still working hard to justify others that it wants to keep: making MC obsess with getting stronger and making it work like a game where whoever gets the last hit of a kill gets exp, so MC will be stuck in loner personality syndrome, hide-your-origins-trope, hide-your-power-to-some-degree-trope.
I felt like when it was revealed that the Guild Master could pretty much tell he wasn't from that world by the language he spoke AND the fact that this world is aware of people coming from other worlds, the whole hide-your-origins-trope should've been dropped in favor of better acclimating to the world by way of people being made aware that he's not from there. That doesn't mean he has to walk around screaming it from every mountain top, but it would also explain his ignorance of a lot of things. He decides he doesn't like the Guild Master for being deceptive but MC is also being deceptive. If you want to garner a relationship of trust, you have to drop some deception in some areas, especially if you know you've been caught in one of those areas.
The fact that he can't see the Guild Master's side of things and only walked away not liking that he didn't just seem like a nice guy "behind his eyes" is also what I'm talking about. It's one of those things where Isekai characters treat the world that's a real world too much like a game, or book, or personal adventure or whatever and can't consider there are other factors going on.