I think it’s a “if all you have is a hammer” situation. In my experience and from talking to different therapists CBT is ill-equipped to deal with existential problems because it doesn’t embrace them or helps patients learn from them. Existential therapy or other forms of psychoanalysis is better suited, in my opinion.
I agree with your take on CBT and existential problems (although CBT is incredible for many other types of issues). Do you have more details on therapies that are useful for existential types of problems?