3.5 year old doesn't care about the potty

Hi there, my daughter doesn't seem to care if she uses the potty or not.

She's been "in progress" since she was 2 years old. We'll try for a couple weeks, and when it would devolve to tears or anger we would put a pause for a month or so then approach it again.

We've tried rewards, celebrating, explaining...honest I don't know what to try next. We have to make her go sit on the potty, she will sit there and pee, sometimes poop. But if we don't tell her to go potty she'll go in her undies every time. She doesn't care if she walks around with poo or pee on her. And even when we are reminding her to go, her undies will have a big wet spot.

I guess my question is, how do I help her learn to better control her bladder when she doesn't care either way?