Life is not a race. She does not have to know now what she is going to do. And, kudos to you for making sure she knows that. Taking a job it not a bad idea.
As @compmom points out, there are lots of jobs that would enable her to work in the areas she has targeted.
More importantly, @Emmycat, it may reduce your D’s stress to know that for many people, they don’t make one career choice but make many. I know one doctor who practiced cardiology before realizing that most of the problems his patients were suffering were caused by diet and exercise. While working as a cardiologist, he got a degree in public health and began studying the effects of nutrition on health.
The world is changing very rapidly for good and for bad. I used to tell my kids that the two careers I have had for the primary bulk of my adult life didn’t exist when I was in college. It was the capacity for flexible thinking, the ability to learn new things, and a core set of skills that has enabled me to navigate from being a business school professor to finance (not my field at business school) to a consulting firm in the field of my research and a co-founder of various business (quantitative hedge fund, tech startup in the HR world, tertiary wastewater treatment, etc.).
I’ve been fortunate to live in a world with people doing really interesting an important things and whose careers are more a calling than a job (people sometimes assume that this means they are choosing not to be paid, many of these folks make lots of $$ and do things they feel are deeply important). My observation of my own and others’ paths is that it is important to do a great job at each step of the way as that will open up opportunities for the next step, which may only be tangentially related to what one is currently doing. Your D’s assignment, if she chooses to accept it, is to refine her sense of what feels authentic/fulfilling to her while doing a great job at whatever she is currently doing. Then, when opportunities arise, she can choose those that feel like the right steps along her path to a fulfilling career. The trick is to be open to and prepared for serendipity.