Writing seemed to make the characters kind of sketchy. Don't know if it was intended to show the nature of identity on multiple timelines (?)
but they seemed more like subjects in an experiment. The parts where Sydney attempts to correct the undesired timeline resulted in some intriguing alt. timelines. In my opinion, the ending was conclusive. She made a decision leading to an untampered timeline where the future is uncertain
spawning an alternate timeline where she's still trying to correct it. She seems comfortable with uncertainty.