https://www.mangago.me/read-manga/monochrome_rumor/ its pretty popular but it is soo good and its def a slowburn
Most shounen-ai you don't have yo worry about they boning immediately. The problem with a lot of serialized comics like manwha is they need to get engagement etc so they put sex immedately to draw in the horners, so reading smutty BL is going to usually douse you in smut immediately. A lot have flashbacks to before they be fucking though

Can someone suggest me a bl which has good plot and like they dont start having s-x first thing straight. A good slow burn, I have read most of popular once. Pls suggest!