Anthony could have just sent Jerry to the Mirror Dimension, but Anthony wasn't too confident about that. If this Eternal Apex could bypass the restrictions of The Sleeping Hollow like it was nothing, who was to say the same thing couldn't be done to the Mirror Dimension?
As for the Divine Realm, it was a gift from ??? himself. This Eternal Apex could only try to find Jerry, but would definitely end up with no leads. But Anthony didn't send Jerry into the Divine Realm without precautions. After all, he didn't want the boy walking around, seeing how amazing the Divine Realm was, and eating one of the Law Fruits.
So, Anthony simply sealed Jerry within his own building that was inside the Divine Realm. There, Jerry could relax, eat, sleep, and do whatever he wanted until Anthony had this Eternal Apex sorted out.
