First, please plan to spay her if you aren’t already planning on it. Female rabbits have very high rates of uterine cancer if they are not spayed.
Spaying will also help with the litter box habits.
That said, bunnies will often toilet on soft things. My girl Bertha cannot have a soft bed because she will pee on it.
For now, I would remove the bed, and have the only “soft” area in the cage/pen be the litter box. Many people like carefresh bedding for litter training because it is soft and fluffy. Place the box in the corner that she pees in the most. Mop up any pee with a paper towel and place it in the box. Clean up any other areas where she goes with white vinegar.
I also can only have hay in the litter box with my buns. Bunnies tend to toilet when they eat hay, so having a hay rack over the box helps with that. Alternatively, have a “kitchen” end of the box with hay, and the other end without hay.
The other thing is when the cage is very small, bunnies often see the whole thing as their toilet, so if things still don’t improve after you take the above steps, increasing the size of her area might help too.
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The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.