i agree with your definition of bromance. there's a different western fandom term for what's happening with Guardian and all the drama series adapted from BL source material: queerbaiting
about how much BL is allowed, i think dramas can hint quite a bit with physical contact and ~staring~, as long as the admission that the relationship is romantic/sexual is never made. I saw a webseries last year that, after struggling with censorship for over a year, managed to get in one "I love you" line in the last episode. funnily, the character couldn't even say it out loud, he was just thinking about it in his head. but i could tell the production crew really tried their darnest to retain that one line in just to give viewers some sort of confirmation, and props to them for that seriously lol.