What's the "purpose" or "goal" of Existentialism?

I'm a lay person, I come from finance and accounting, not from humanities, so my knowledge might seem too simplistic for some. Also a staunch atheist. I know Existentialism is not a single, rigid and cohesive ideology, lots of "existential" authors despised and criticized each other, I understand that.

To me, Existentialism is a philosophical tool to liberate oneself from the constraints of society. By recognizing individualism, the absurdity of existence or that life has no inherent purpose or meaning one becomes unchained, free to do, believe and follow what they please (within the constraints of what's currently legal in society). I firmly believe Existentialism could easily replace any religion in 2024 western society, especially if one is atheist/agnostic and constantly studies the subject.

What do you think about this?