oh interesting, i feel like there's an intersection of reasons as to why unique ship/chemi names have become more and more popular 1) companies leaning into ship marketing in an increasingly meta, self-aware way 2) eastern/western fandom cultural differences. i think nowadays new kpop idols are extremely aware of the effect their individual friendship dynamics have on their fans, and undoubtedly they're encouraged to come up with unique "___ line" or "___z" for chemi/pairing names. some of that is definitely due to oversaturation of names/syllables/you can only rearrange them in so many ways as we are all the way in 5th gen now. the 4th wall barely exists anymore at this point LOL. however i think you'll find that when it comes to actual k-rps circles (especially on ktwt and postype) kfans will still use ordered ship names to indicate positioning and dynamics as that's nonetheless a big part of how east asian shipping fandom works. western fans on the other hand don't tend to have the same culture of rigid separation with regards to order preferences, so i feel like they adopt the unique non-ordered names more avidly, or at least use it in an all encompassing sense (ship/friendship/fic/either dynamic) because order doesn't matter to them, and the ship is the ship no matter what. a lot of the time ifans will just go with "what sounds better" to them. sometimes kfans will still use a ship's unique (non-ordered) chemi name when referring to the pairing in general; it’s just that if it's fic or a specific agenda, i find that they still do prefer to use ship names that have order indicated already (especially in their bios or in fanart captions).

haha wrt jmjn specifically… i mean i have seen some fans call them both, i think it really just comes down to personal preference and the fan culture you've adopted. i don’t know if this is entirely accurate but i do get the feeling that in eng speaking fandom and among ifans jmjnists are more rigid in their preferences, and there’s more of a general switch ok vibe with nominists/the term nomin in general… if you’re really strict about it in the opposite way then you’d probably call them jenjaem. i myself do call them jmjn out of preference and habit but since nomin still refers to the ship in general among ifans, i have used it for seo when ficposting 😭 i hope this helped clarify the shift/divide a bit!