Something I really don't like about this series is that none of the "bad" designs are actually bad. Nightmare actually looks very cute as a mascot for eldritch theme.
In a swamp of Isekai reincarnations this one feels so unique and refreshing. In the little bits of worldbuilding the world feels lived in, and the MC herself is a rather cute character.
You know, people always joke about how white people love cuck porn and try to justify it, but only the Japanese would make a whole ass published manga about a guy watching the girl he loves fuck other people.