A picture of the set-up, especially when soiled, can be helpful for members to give specific suggestions.
Generally, the bigger the litterbox, the less likely peeing/pooping outside will happen. As rabbit owners, we need to remember that the actual structure/perimeter of a litterbox is only meaningful to us humans– there’s nothing in the nature or intellect of a rabbit that tells them, “Ah I should just go inside of this random object”. It sounds like she is peeing around the area of the litterbox, which for many owners is actually categorized as a win in litterbox habits, haha.
There are some litterbox training strategies outlined here: https://binkybunny.com/infocategory/litterbox-training/
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.