I was doomed from the start with this one because "siblings to lovers" is not a format I like no matter how you spin it, but Adachi doesn't go too heavy into the romance angle, thank God.
However, the entire manga has bizarre pacing, the jokes are stale, and he has more characters than he seems to know what to do with. Chapters will end abruptly on half-jokes or implied reveals with all momentum brought to a screeching halt. The fourth wall jokes don't bother me as much because I do find them fairly characteristic of Adachi's style, but man, this manga has tone issues. It'll have a cheap throwaway gag breaking the forth wall and then have a guy getting slit open by a katana a few pages later. It wants to be silly and taken seriously at the same time, but does not juggle the two approaches elegantly at all. It also wants to be a commentary on environmentalism, but is too unfocused to say anything particularly striking or meaningful.
Also, why are several characters perversely interested in their own sister? Blood-related or not, shit's weird, isn't it? That outright made a couple of the all-too-many siblings far less endearing to me, which made their entire journey a slog because I didn't want them to stay together as a family! Natane, get out of there, your weird older brothers want to spy on you in the bath!!!
Asajirou is moe though. Asajirou did nothing wrong.