Almost every time that I hear or read “existential,” I am unsure what if anything is meant.
The speaker or writer does not mean “of or pertaining to existence,” I presume. The writer or speaker means “of or pertaining to existentialism.”
I guess an “existential dilemma” could both involve a dilemma and pertain to existentialism. Does it usually, or does it sound profound but betoken nothing? What about an “existential crisis?” Or does “existential crisis” drive us back to “of or pertaining to existence?”
I dunno. That is what concerns me.