Partner's Parents Expect to Know My Salary and Student Loan Details

TLDR; I (27F) don't know how to set proper boundaries with boyfriend's (28M) parents concerning my salary, job choices, student loans, and investments
I've been with my partner for 7 years, and his parents have been asking me incredibly personal questions, which is driving me insane. For example, I recently received an offer from my dream workplace, and over dinner, they outright asked me what the salary is and seemed upset that it isn't quite as much as what I'd be earning in the private sector. From there, they started questioning me about my student loans in an effort to get me to tell them the precise amount I have. For context, neither they nor their children have any student loans. This is at least in part because they come from a much wealthier background than my family, but is also due to the fact that both of my partner's parents completed all of their education overseas where it is free. By contrast, I completed all of my education in the US, including graduate school, and come from a working-class family. I've worked incredibly hard to get where I am and I don't think they have half a clue as to what that was like.
When my partner's parents ask these questions, he is always silent and refuses to set boundaries. Unfortunately, they never seem to ask these invasive questions of their own children, only of me. How should I go about setting proper boundaries with them?
Edit: my partner and I openly discuss finances and he is not unhappy with the job offer I received or my student loan debt.


Source.