The Bronze Age collapse is really just guess work nothing is definitive. The Sea People narrative is mostly based off of a couple of Egyptian texts that could be used to explain why everything “collapsed,” but very few sites in the Levant show signs of actual warfare, rather many seem to have just been abandoned or burned, but not necessarily in fighting. Eric Cline talks a lot about this, but it seems that it was probably related to long period of drought that led to the collapse. We can tell that there were major droughts due to pollen analysis from soil cores, and this is corroborated by hittite, ugaritic, and Egyptian sources all discussing famine. This further would explain why the Sea People went to Egypt, as they were almost certainly Greeks leaving their homeland. We can tell this due to various things, but the major red flag is the philistine culture which appears in Palestine, because they basically pop up out of nowhere in the archaeological record using Greek style pottery, hearths, architecture, etc. they also have done genetic analysis on philistine bodies and found that they were of Greek ancestry