I would prefer shounen ai/yaoi but really, anything can come! I read novels where a girl disguises herself as a boy, but have never read one the other way! I only read a manga, but I forgot it’s name. It was about an emperor or something wanting mc’s little sister in his harem, but mc couldn’t let that happen so he disguised himself as his sister.
https://www.novelupdates.com/series/how-can-the-saintess-be-a-boy/ don't ask how i know 'bout this novel... i don't have a few weird fetishes
Starchild escapes arranged marriage. https://www.novelupdates.com/series/starchild-escapes-arranged-marriage/ The MC spends a good part of the story disguised as a maid, as his four evil exes are hunting him down. MC is totally straight but I find straight guys who are forced to cross dress strangely hawt
I think the manga you are thinking of is Prime Minister in Disguise / 代嫁丞相 As for rec, there is a manga that is three people transmigrate into a game, the mc is a girl and the other two people that transmigrate are two guys and the two guys turn into a girl in the game. Xuan Ji Ci / 璇玑辞. I've only read a few chaps before putting it on my read later list but it's good so far, i think i stopped around chapter 80.
There’s an arc in Card Room where two of the male characters need to cross-dress (one of them being the MC) to disguise and play their designated roles. It’s actually also an emperor type setting lol. Also not quite the same, but the ML in Kaleidoscope of Death cross-dresses and...just lets people misunderstand lol.