I’m not adamant that the Trojans did not have Greek antecedents. It is definitely possible. However, I still think it’s not certain.
Another suggestive point for the Trojans being non-Greek is how Homer lines up the gods for the two sides.
GODS who favoured the Greeks included: Hera, Athena, and Thetis.
GODS who were uncommitted were: Zeus, Hades, Hermes, Iris, Persephone and Demeter.
GODS who supported the Trojans were: Aphrodite, Apollo, Poseidon, and (for a while) Athena.
Now, clearly these are all Greek names for deities but the fact that there are 2 opposing camps of gods *might* suggest the two sides worshipped different gods. It was common (cf the Romans) to label a foreign god with similar attributes with the name of a home grown deity.
Hence, the very definite possibility that the Trojans were not Greeks & had their own, different culture.