I won't speak to what "colloquial Nihilism" is because I think this will be highly dependent on your personal experiences. I think you're basically right about

I won't speak to what "colloquial Nihilism" is because I think this will be highly dependent on your personal experiences. I think you're basically right about what nihilism is, but I don't find the main insight to be disturbing at all. I never truly felt free, liberated, until I had that insight. Prior to that insight, in young adulthood, I explored Hedonism and Existentialism, but it turned out that the secret is to just stop caring about it all so much and just live/die/whatever. Let it be. It brings me joy to not care if I live or die, though my instincts will tend towards keeping me alive. It brings me joy to not care if I succeed or fail, although it's fun to Try sometimes. I enjoy trying to do right by others, raise good kids, but I don't worry about it when I fail. It's just a ride; people get on, people get off.