Holy fuck I don't mind a chapter or two dedicated to filler characters but it's been going on way too long especially with a character as boring as this girl.
This manhwa wouldn't really be defined as isekai but tensei (rebirth). Both genres however generally are very similar in terms of setting and narrative so they're often grouped together. It would probably be best to just make the tag isekai/tensei so people can stop arguing about genres.
God damn LH's translations are fucking atrocious and unreadable. I at least know some moonspeak, so I can just reference the raw if what I just read made no sense but these translations can really diminish the experience dramatically for english only readers. Here's some quick fixes for some of...
In the raws she actually yells バッカじゃいないのおぉぉぉぉぉぉ (Romaji: Baka janai nooo Literally: Aren't you an idioooot? Localized: Are you out of your mind?!). The subject isn't stated but it's safe to assume the subject is Jin in this case based on context so she's actually calling just calling Jin a baka.