I've seen theories that they may have been more closely related to either the Minoans or the Indo-European peoples who inhabited Anatolia at the time; hence their collapse was due to invasion by Greek-speaking peoples.
There's always more to be said on the topic, but u/Daeres touched on this in How does Mycenae relate to ancient Ancient Greece?
Also see u/UndercoverClassicist's discussions of the transition from the Bronze Age to the Iron Age in Did people realize they were part of a civilizational collapse during the bronze age collapse? and Do we know how the general population of the Eastern Mediterranean was affected by the Bronze Age Collapse?
I recommend also checking out a couple of lectures by Dimitri Nakassis on this topic, "The Mycenaeans in Greek History: Orientalism and Master Narratives" and "Orientalism and the Mycenaeans." Summary:
Although the decipherment of Linear B as Greek in 1952 confirmed for some the essential unity of Hellenic prehistory and history, for others it illustrated the sharp break between the Bronze and Iron Ages. Moses Finley in particular argued vociferously that “Mycenaean society… was not Greek” “in any significant or proper sense,” and his interpretation has become historical orthodoxy, especially but not exclusively in Anglophone scholarship. In this paper, I examine the arguments deployed by Finley and his intellectual successors, and I argue that the underlying narrative is entirely Orientalist sensu Saïd.