What Should I Do After Suddenly Transmigrating to an Ancient Imperial Harem?

A gloomy shut-in somehow transmigrates into the imperial harem. She refuses to put up with it. She wants to make it back alive. Everyday harem life, with the protagonist's thoughts woven in. The story occasionally takes a fantastical turn. A bizarre idea born from a nightmare. The writing is clumsy and the story is short. You can tell from how the author names characters... The heroine is gloomy, so there's no way she'd survive to the end without a few cheats. No CP, though there may be a little yuri-style romantic tension... If you spot what seems like some old-fashioned mockery in the story, that's right, the author is mocking it. The ending is a happy one by the protagonist's standards. Theme: