The only one who won was Miko. She got everything she wanted. Everyone else had to compromise in some way or form.
Yeah, from the links to certain parts of this manga, this last chapter, and overall comments - it all seems like an influencer level artist and cosplayer couple had their fetishes of swinging, NTR, and stuff, and their "lame" friends had crushes on them - so the cosplayer manipulated all 3 of them to have what she wants - her boy-toy horny as fuck after cheating/NTR, soy-boy big dick toy to fuck her whenever she wants, a big-tits girl to play with her boy-toy and use as a jealousy production tool for the soy-boy, etc.
Sure they all seem happy at the end, but in reality only cosplay girl is happy, the other 3 probably have some hidden resentments/regrets. Thou I would probably need to read it whole to get a proper "feeling" about it, but I am not a fan of NTR-connected dramas so reading this would probably anger me, especially that I don't really like either of the girls visually. Thick girls are fine, but I don't like huge tits, and the cosplay girl is still on the big side in rack department
Edit: I checked like first chapter to see how it starts, and it seems that soy-boy and monster-tits felt inferior to the cosplay girl and artist dude, part artist knew soy-boy has monster cock, and cosplay girl has huge ego, likes being a couple with popular artist, but she yearns for a huge dick as artist boy is a small-toy if you will. So this like points to it really being a one manipulator fucking over a couple and boy-toy to have her perfect ego life.