What would you do?

I've been working at the same job for almost 3 years. I accepted it because I was told it would be very challenging and rewarded. What it actually turned into is me sitting around twiddling my thumbs, scrounging up whatever work I can. When I go to my boss and ask for more, he gives me the bare minimum and I'm done with his assignments in 5 minutes.

This isn't actually the problem. The problem is how this is being perceived by his daughter. Now, this is just my assumption, and I know when you assume...it doesn't work out well. BUT, from how the daughter treats me, the micro-aggressive interactions we have where she subtly implies I don't do my job, and the way she speaks to my boss about how some of the tasks on her plate could go to me, I can tell there is some resentment there. Nothing I've personally done, but her dad hired me and doesn't utilize me the way he could, which leaves a ton on her plate.

I have asked him for more work and we know how that goes. I've had conversations with her after she has blown up on me telling her I am here to help and I just need somethings delegated to me. Without them being willing to let go of some of the tasks they have, I am left with hardly anything to assist with, hence my thumb twiddling and doing other tasks that don't take a lot of my time. And trust me, I LOOK FOR THINGS TO DO because I am someone who can't stand having nothing to do. Lacking purpose makes me feel invalidated and unfulfilled.

So what would you do in this position? The daughter continues to bully me because she's resentful of the workload I have vs. the workload she's got. On top of that, we have no HR because the company is incredibly small. When I was hired, I was told the daughter would be my go-to for any issues since she's very "compassionate". YEA RIGHT.