Well, the thing is, characterising it as a catastrophic, all-encompassing 'collapse' may be Iffy. (I'm reminded of a later period held in the same view whose degree of catastrophe is also under debate.) More can always be said on the matter, so if anyone would like to contribute further, don't let this post stop you! In the meantime, OP, you may be interested in the following posts on exactly just what happened in the later parts of the Bronze Age:

• For the classic 'Collapse' narrative, Eric Cline, author of 1177 BC: The Year Civilization Collapsed, did an AMA with us when the book dropped;
• u/Bentresh examines the Collapse as experienced by the Egyptians and the Hittites;
• and u/UndercoverClassicist provides an alternative view to the classic thesis, questioning whether it was a 'collapse'.

Also, one more link in next post because argh tag limit.