We're talking about a Levantine Iron Age text discussing Bronze Age peoples where civilization collapsed in the interim. In the case of Ḫattuša, the state archives were almost certainly unreadable by the time the Biblical texts were written, evidenced by the lack of any Hittite cuneiform texts being produced or copied in the Iron Age. Egypt and Mesopotamia maintained texts and the ability to read those texts across the collapse. The same cannot be said about Syria-Anatolia and the Levant.

That isn't to say that the Biblical texts can't reflect a memory passed on through oral tradition or knowledge from Mesopotamia and Egypt. But given that the geography of the Hittites of the Bible seems to line up more with the later "Neo-Hittite" Luwian-Arameans than Ḫattuša and that the Bible doesn't seem to be aware of the empire of Ḫattuša, the Biblical Hittites are probably not Ḫattuša.