For me it’s financial, though as a middle-aged person I am nowadays also plagued with metaphysical questions.
About the financial part, I’m actually very well-off but the world has become such a complex place (or it always was and I am only realizing it now at my age) and I have little to no control over most aspects of it. I don’t want to lose what I have worked towards because of geo-politics, climate change impact, global recession, or such things. It’s not an existential crisis for me but there is some amount of anxiety and dread that I previously did not have.