Okay, I'm on your side on this one OP, but let me play Devil's Advocate here...
Perhaps your GF is worried that you will get stuck in a rut and become depressed? I often feel this way when I don't have a routine to keep me busy. At first I enjoy the feeling of not having to wake up and go to work every day, but eventually all of the things that bring joy into my life become less fun, and I start to feel bored and unfulfilled.
Here's another angle: Maybe she thinks there may be a possibility, however slight, that the passive income might not last, might not keep up with inflation/rising costs. or might not be enough to cover a large expense like a medical emergency or catastrophic disaster?
I know if I were not working, I would be worried that I would be falling behind on my professional development, and if I ever did have to get a job again, I'd have a massive gap in my work history. Sure, you could always lie and say you were "self-employed" or whatever, but if you aren't keeping up with the industry, you might not have developed skills to just jump back in at the same level you were at before.
Okay, done playing the Devil's Advocate. Here's my thoughts:
I don't think your GF is wrong for wanting to be with someone who has some career aspirations or ambition, but like most relationship problems, the solution is to sit down and talk out. First you need to establish some clarity. What are her expectations for you? Why does she feel the way that she does about working for a living despite having enough passive income to live comfortably? Why would you not working annoy her? Why does she care so much about developing yourself, and does that development strictly need to be tied to a job where you collect a paycheck?
Once you've figured out why she feels the way that she does, it might be possible to either convince her of your viewpoint, or come to a satisfying compromise. Would she be satisfied if you took one of your fun hobbies and made it a side-gig? Would that count as a job according to her criteria? Most people can't do that because it's hard to pay bills without taking all the fun out of it being a fun hobby, but without the financial pressure to produce, you could take it at your own pace, take breaks, do what you love and still make a "career" out of it.
What about school? It's not a job, but lots of people enjoy learning and if I did not have to worry about working to live I would absolutely take community college courses on topics that I'm interested in learning more about. That's another form of development that she might find acceptable in lieu of a job.
There are also more traditional "fun" jobs that have you working for an employer and collecting a paycheck that you might be able to tolerate on a part-time basis. Think big - work at an ice cream parlor in the summer, or wear a mascot costume for a sports team, or volunteer your time at a charity. These are things no sane person would think of as a career, but they could be entertaining or fulfilling distractions from your regular day-to-day if you are okay with doing them.
Again, I don't think you are in the wrong for wanting to stand your ground on this. These suggestions are just for if you want to do it to make her happy. You have the luxury of being able to not work, and that's an incredibly rare blessing. You shouldn't have to compromise on this just to appease her. If you want to take advantage of this unique financial position you are in, she should be able to understand that desire. If she can't, maybe you two aren't compatible? It's definitely a no assholes situation, but if you can't agree on something like this I would say an amicable breakup is warranted. She can romantically pursue someone who puts more value on work, and you are not reliant on her financially, so you could just be friends instead.