Extremely tragic BL manga that's actually enemies to lovers and it's a war and they're on different sides and the BL part is only like a side plot to the point that it's not an actual BL but a seinen war manga and it's like 5 volumes and like the characters are actually confirmed gay and deal with homophobia both internalized and from their militar......
basically, boy A and girl A are a couple, and both of their respective same-sex best friend are a couple as well. however they dont know that their respective bffs secretly pines for them and just got together for *plot* reasons. the story is just about boy A and girl A falling out of love with each other as they fall for their bff instead.
Story trope you wanna see