Ye Jiuyou might never experience what "entering the Secret Realm" feels like in her lifetime, as the places she's been throughout history are always someone else's Secret Realm.
When the perspective extends beyond the domain, one realizes that the universe can be her Secret Realm everywhere.
To this day, Ye Wuming's cultivation no longer overshadows her, yet everyone, including Ye Jiuyou herself, still agrees that Ye Wuming is the strongest, simply because she started early and has seen more than anyone else. Ye Wuming must have explored the black hole and more things that now make Ye Jiuyou's heart flutter, at least gaining insights from the periphery.
So Ye Wuming has the qualification to set up confrontations with Others from the Other Shore before she herself reaches it.
