Here is a title from an official channel: a short posted by TWS called "#SODASODA with 42". Read cold, the 42 looks like a count of something — takes, days, people in a room. It is none of those. 42 is what TWS call their fans, and the short is a clip made with them.
That is the whole trap. A fandom name is simply the group's own word for its fans, and Korean groups put it into titles and captions with no explanation, because to the audience they are writing for it needs none. From outside that audience the same word reads as a typo, a hashtag glitch, or a number that got left in.
The shapes vary and that is why there is no single rule to spot them. Some are invented spellings — Red Velvet call theirs ReVeluv, ARTMS call theirs OURII, ONEWE call theirs WEVE. Some are plain English words used as a name, like aespa's MY or Stray Kids' STAY, which slide past you in a sentence. And a few, like TWS's 42, are not words at all.
A short reference, all of them names the groups use themselves: BTS have ARMY, TWICE have ONCE, SEVENTEEN have CARAT, IVE have DIVE, LE SSERAFIM have FEARNOT, MONSTA X have MONBEBE, i-dle have Neverland, Stray Kids have STAY, Red Velvet have ReVeluv, aespa have MY, ARTMS have OURII, ONEWE have WEVE, and TWS have 42.