some people (not on this website) seem to say "existential risk" in ways that seem to imply they don't think it means "extinction risk". perhaps literally saying "extinction risk" might be less ambiguous.
A salient and arguably valid non-extinction meaning for "existential threat" is "the firm will go bust". So currently many companies are considering if failing to use AI could be existential. Economic and national security implications make this meaning applicable to countries, thus governments are considering if failing to do well in the AI race could be existential.