Despite modern maps showing Western Anatolia as Hittite controlled, they were not. There was a broad J-shaped band of independent and federated vassal kingdoms (running from north of Wilusiya, down the western Anatolian coast and interior, and along the south coast until about the land north of Cyprus). These vassal kingdoms sent tribute/protection money to and raised warriors for the Hittites but these kingdoms, which were for all intents and purposes otherwise sovereign states, could not depend on the Hittites for local defence.
What’s more these western Anatolian kingdoms were rich states with very substantial mineral resources, located along busy trade routes and some of these kingdoms and confederacies could have rivalled the Hittites in their wealth if not their military strength. One such vassal kingdom which later went rogue was called “Mira” and according to the Beykoy inscription discovered in 1878 (but just translated and published in 2017) it was Mira which was the protector of Wilusiya (Troy?). King Kupanta-kuruntas apparently was the name of one King of Mira c.1190 BCE and he or someone like him would have been charged with aiding the Trojans in their time of need. The Hittites were pretty busy at this point dealing with palace intrigues at home and Gasgan/Kaskan raids/invasions from the Black Sea coastal region noth of the Hittite heartland, as well as defending their eastern frontier from the Mitanni, Assyrian and Egyptian Empires.
In the interests of objectivity, I must report that the authenticity of the Beykoy inscription is being disputed by some scholars and proving its provenance is difficult. The original stone inscription was destroyed when local Anatolian villagers broke it up and used it for building materials in the foundation of a local mosque after it was excavated out of the ground. Fortunately paper copies were made by archaeologists on the scene during the excavation and those copies were rediscovered among the personal effects of an elderly British archaeologist who died in 2012. He was the last of a group of scholars who tried unsuccessfully to decipher certain Luwian writings which have only recently been understood.