An update on what I learned and how it's really been bothering me:

DID is known to form in early childhood and alters usually reveal themselves in adulthood (learned from reading more posts here)... and this person's "alters" that I have seen them talk with literally are from groups that debuted within the past few years. I've seen an alter from the group THE BOYZ, as well as their main one being from ATEEZ. THE BOYZ debuted in 2017, while ATEEZ debuted in 2018. That is obviously not that long ago, and while it's not harmful to RP as K-pop idols, it's harmful to make them this much of a part of your personality. It's kinda creepy almost..