
Yesss. Very well said! Honestly, at first (when I looked at the cover of this manhwa), I thought Joy was a guy!
I really wish for the character Joy to have some sort of build up, like why is she currently not looking for a relationship? Is she like Mel Sievers who has been burned before? Hmm. It's an unpopular opinion but I really like the "get someone jealous to realize their feelings" trope.
I REALLY REALLY like Jooyoung too, but since she's not even in the cover, I doubt she'll even end up as the one making Dahye jealous. Dahye is most likely end game but I hope it progresses in a way that you would want to root for them.

First off justice for Jooyoung, I love her so much.
Although I wouldn't mind Yuna ending up with Dahye, I really hope its Joy instead. Like you mentioned butch lesbians are few and far between in GL and I adore Joy's character design. I agree that the pacing of this story thus far is really fast (why we goIN SO FUCKIN FAST) and I really hope we learn more about Joy than we do now.
Recently I feel like GL has had some abrupt ending without true closure and I hope that that's not the case with this one. Honestly I just want good things for Yuna <3
I'm a bit concerned about how fast this is going. I thought of it as just poor writing at first (it went from very little progress in the story in the first 15+ chapters to Yuna thinking she's falling for Joy, which is textbook bad pacing), but the more I read the comments, the more it seems to be a setup. A lot of people mentioned that Joy might not be endgame because of how often she's been appearing in the past 3-4 chapters. I'm beginning to agree with the conspiracy theories.
Narrative-wise, what motivation does the reader have to hope that Yuna ends up with Joy? I know everyone and their mother has been simping over Joy because she's attractive, but we barely know much about her outside of the fact that she likes 1) work and 2) Yuna, for some reason. She was barely set up in the first several chapters...unlike Dahye and Jooyoung.
I'm not a fan of the possibility of Yuna ending up with Dahye because Dahye is *that* straight girl we all know, but we have to think of the narrative power this unrequited love Yuna has for Dayhe possesses. The "oh no, I'm in love with my childhood friend" trope is an old and powerful narrative artifact and, more often than not, the best friends end up dating by the end of the story. There is a high chance that Yuna will just end up with Dahye, especially now that we got a glimpse of Dahye possibly being jealous of Yuna hanging out with other people. I'd also like to add that Dahye is not a bad person. She can be insensitive at times, as Jooyoung pointed out earlier on in the comic, but she's an overall decent, kind person: she was willing to give Yuna a chance when all the other girls thought Yuna was "seducing" boys, defended her against the boy she liked, and probably cut off a date just to wait for Yuna to wake up after she collapsed drunk in the bus. She's an awesome friend, so, again, high chance she'll sort out her feelings and get with Yuna in the end.
Here is where I'll come clean and say that I absolutely love Jooyoung. The chemistry between her and Yuna is legendary. They have a nice and easy rapport, where Yuna obviously feels comfortable with her when she feels comfortable with no one else. Jooyoung is honest, hilarious, and smooth. She is constantly toeing the line between teasing and flirting with Yuna (it has "the probability of Yuna having sex with Jooyoung is vert low but never zero" type of energy). Yuna went on her first date with a woman because Jooyoung point-blank asked her out. I'm not saying that they should end up together because, at times, the feelings just aren't there, no matter how great the other person is. I just wanted to point out that every time these two have a chapter together, there is great chemistry between them. However, she has the least chance of ending up with Yuna because, well, she's not on the cover. She has no place in this "love triangle", which pains me to say.
Then, we have Joy, who we barely really know as a character. I'm a big fan of her design (butch characters like her are sort of rare in gl, so she's a breath of fresh air), but her character and narrative purpose seems to pale in comparison to the other characters I just mentioned. It could be the author will just rush into having Yuna date Joy, only to make Dahye jealous. Which would suck, to be honest, because I like the idea of Joy. I just wish that we got to learn more about her as a character, instead of a beautiful piece of cardboard.
TL;DR: The relationship between Joy and Yuna is going far too fast. Yuna has more chemistry with Jooyoung and even Dahye. Hope that changes because Joy is great to look at.