Yes, the ancient religions (from Celts, to ancient Rome, to ancient greeks, to ancient egyptians, to canaanites, to Ugarites, to ancient Israelites, to mazdeans,…) were all polytheists. On the last 3, the Old Book confirms (including King Solomon).

Also, the current ‘’Western’’ monotheist religions did not pop up out of nowhere. They have many roots coming from polytheist areas : Osiris/ Egypt, Ugarit (Gods El, Yahwe, Baal, etc), Zoroastrism, Mesopotamian civilizations,….

The Christian’s eschatology contains all the many elements of the Zoroastrian eschatology (which was described nearly 1000 years before Christ)

The Christian Eusebius of Caesarea described the monotheist Zoroastrian definition of God as the best definition of the Divine.

Therefore, I am not convinced of a real ‘’clear cut’’ between East & West.