SPQR? Who?

[Fluvius Camillus]

Christianity will not exist because the Parthians will conquer the Seleucid domains and Judea will be an ally or protectorate of Parthians and the Jewish society won’t require a messiah to free them.
Probably the Hasmoneans and the Ptolemeis will remain in power as puppets of Parthians. First, they will require Parthian help against the Seleucids, and later to remain in power. I imagine this because in real history they allied with the Romans against Seleucids, and with no Romans it's naturally they will go tho the Parthians

Maybe John the Baptist and Jesus will manage to reform the Orthodox Judaism but it will be a reformed Judaism (not Christianity), only for Jews. So please try to imagine the historical evolution without Christianity and Islam......
You have Zoroastrianism, Zalmoxianism, Germanic and Celtic Polytheism....etc. so live Christianity and Islam
You could imagine however how the Phenician religion will evolve in South-West, perhaps will evolve in monotheism, with Baal as the only god.

Says who?

Without Magnesia or without Roman intervention when Antiochos IV Epiphanes was at the gates of Alexandreia, the Seleukids were not as weak as they sometimes seem.

Rome would not tolerate a powerful eastern kingdom (Ptollies, Seleukids). Without a supreme power in the west who is policing them, the Seleukids could have had much more and been far more stable (no Rome setting up rival kings for example).

I have no time now to write a full world review, so I'll do that another time, I just wanted to point this out.

~Fluvius