Responses
No I'm pretty sure it was juhee because juhee wasn't wearing any pants with a really short hoodie + blue girl is also his neighbor so that question is not applicable to both either way. But from that girl's behavior it was clearly juhee because she was very bold and banging his door instead of a simple knock which is very juhee coded unlike the shy blue girl

****
I searched for another site to read the complete version.
Somehow, the blue girl one realizes the guy has real feelings for the gacha girl helps them by locking namjoo with juhee in juhee's room and they had plenty of sx.. she decides to give up her feelings for namjoo becuz "juhee is not a bad girl, i would have not given up if it was otherwise". Juhee and Namjoo confessed to each other, said ily and whatnots
The next day, they come face to face with the blue girl upon opening the apartment door AND THE BLUE GIRL SAYS SHE WILL NOT GIVE UP AND SHE NEEDS A DOSE OF THE GUY WHATSOEVERRR
The end feels like Namjoo continues the relationship with the blue girl one (there was no face shown, it looks like the author just lets the readers think whatever) with the convo going like "why are you wearing something like that, what if someone sees you on the way here" BECUZ WHY WOULD HE SAY THAT TO JUHEE IF SHE'S JUST HIS NEIGHBOR OR SOMETHING but maybe it was something like that loli chapter where it feels illegal for them to be seen together (?)
Idk it was up to the readers to interpret, i guess