Have you tried a long line attached to a harness? That way she can have some freedom but you still have some control. It’s hard when they get set on something, I know.
Spudpup is back from the vets! He’s put on 1.5kg in a week and a half, but the vet nurse said that’s perfect. He’s had a pedicure and a wormer and was very good for both, then lots of snuggles. Then we worked out that he’s far enough past his second jabs to go on the floor, so he had a little explore of the waiting room and walked back to the car on his own four paws! And he wasn’t quite so overwrought in the car - plenty of whimpering, but a lot less yodelling… I had Classic FM on tbh to drown him out a little 
But yay, we can start to go for little walks! I think once we can start going to fun places, he’ll start to like the car a bit more 🤞