Honorifics make no fucking sense on isekais.
Why would another world use them when here we almost never do? Japan is an odd-ball, not the norm. Yes a few languages have some words that themselves work a bit similar in that sense (Korean for example, the classic 'noona', 'hyung' and so on), but still theres no reason for a fucking fantasy world to use the Japanese ones unless they were taught around their whole fucking world by an isekai'd Japanese hero or something like that.