I actually had a resistance to reading/writing rpf for a very long time, mostly because I didn't understand it as separate from tinhatting, which I still do feel vaguely uncomfortable with (not to say what other people's boundaries should be just--that's a boundary that I have with myself). I got into kpop rpf through twitter aus from BTS accounts I followed for jin content at first lol, then progressed to reading actual fic from there! It took a while from then (late 2019) for me to start writing though, I didn't start writing fic until last fall.
I think the thing that draws me to a fic most of all is characterization/character dynamics. I really like fics where a lot of thought has been put into the world and how the characters fit into it, whether that be idolverse or a really well-crafted fantasy/scifi au or even just hyperspecific industry aus (baking! fashion! in a band but not a kpop band!). I don't like things that are /too/ bleak or /too/ mean, I'm a romantic at heart and I want to believe things will turn out okay in the end lol....
Also, this is more group-specific, but any fic that explores Joshua/Vernon/Minghao/Jun feelings about home and where is home anyways and who am I etc etc.....catnip to me always.
Oh! I think I'm drawn to stories that are tonally pretty upbeat and humorous, lots of ensemble antics, but also thematically rich and not afraid to get deep/emotional/sad