High fantasy always works for some reason, with some generic conflict or something that lets the adventurer/commoner speak or interact with noble/royal, usually a running away from arranged marriage or coup attempt or anything like that really.

Modern can work, usually with meeting on like a dating app or in a public place, usually a minimum wage employee that has to assist the wealthy businessperson or businessperson's offspring/family, or a maid if you want to just go for the fetish points, or some kind of traveling storyline can sometimes work.

Afew genres can also accommodate the storylines I just threw out, like Sci-fi which allows for plenty of the same wiggle-room fantasy gives, Historical fiction can, you just have to play with suspension of disbelief abit to make it work, School-life can make it work with multiple angles like wealthy and popular/poor and unpopular, bully to friend to lover, etc. Honestly in deciding a genre for a Romeo and Juliet type story, the sky's kind of the limit if you know what you want.

EDIT: Spacing for ease of reading.