Nothing definitive, I'm afraid. Here are a couple of older threads that discuss this subject --

• Why were the Phoenicians spared the ravages of the Bronze Age collapse?
• Was the Bronze Age Collapse caused more by invasions and migrations, or climatic events?

-- but especially given the speculative nature of the topic, there's certainly room for more answers.

The only caution I'd suggest is that the scale of the collapse is often overstated: the downfall of political entities is really confined to mainland Greece and Crete (the Mycenaeans), Anatolia and Syria (the Hittites), and parts of the Mediterranean coast south from there (Ugarit etc). Other civilisations, like Cyprus, the Egyptians, and the Assyrians, did not collapse.