How do you uncover true motivations and goals during user research?

My goal is to create some UX/JTBD personas and I am new to conducting user research interviews.

When asking participants what motivates them professionally, or what their professional goals are, a lot of them answer with "more money".

From what I've read, you are supposed to try and keep the questioning solution-agnostic, but it feels like I'm not getting to the deeper motivations/goals.

I have tried asking "why" again and they usually look at me like I'm crazy...and respond with something like "to live a more comfortable life."

Should I be framing the question in a different way? Any other suggestions?