I think the show has been pretty strongly hinting that Neal is Bae. But here’s my theory, for something that would make a twist.
Neal is Bae’s son/grandson. He grew up hearing stories about his father/grandfather’s past, so August was able to convince him to leave. The spell Rumplestiltskin did didn’t direct him to his son, it directed him the the person with the closest blood relation, his grandson/great-grandson, Neal.