Does anyone remember the manga where a bullied highschool girl and a depressed adult man switch bodies. It was, I think, tagged as psychological and there was also a supporting character who is a highschool dude helping the adult man to retrieve his body(? I'm not sure about this part), and there is also the girl who was bullying the original girl and has a weird fixation on her

It's based on a novel and it's centered around 2 guys being in an arranged marriage. The mc is really chill and from what I can remember, even sneaked out of the castle to pretend to be a worker. It didn't last long tho and I think he was also pretending to be a woman when he first arrived at the ml's place
Winterfield
Thanks!