ouju (the name itself) was in the leaked lineup of trainees for smngg (now aespa).

"우주" being spelled as "ouju" in romanized version is more likely to differentiate her with other idols/person with the same name, i guess? same with these ones:
동혁 - donghyuck instead of donghyuk
고은 - koeun instead of goeun
규빈 - gyuvin instead of gyubin
윤오 - yuno instead of yun oh