I remember bits and pieces but I do believe it’s an office romance manhwa. I can’t really remember if it was straight or bl but I’m almost positive it was ceo x secretary. The key point is that the side couple was a girl I believe she was related to the ceo but her character design was kind of gender fluid or androgynous in a way. I remember she would be in suits and her mannerisms came off a little more manly. she started a relationship with the second ml. I do remember the second ml being someone who got crushes easily and crushed on the mc but obviously it didn’t work but I think one scene was that he went to a bar and met the second fl and they started talking from there. Please I hope I’m not crazy but I’m trying to find this webtoon if it exists.
For anyone confused on the daddy part it’s the translation. It’s like Koreans saying oppa or in this case since it’s Chinese they say gege. The translator for this is directly translating so that’s why it sounds a little weird.