I’ve had a Litter Robot 4 for a year. I’ve two cats. One of them pees on the sides and on the front. The only “issue” is that some litter can get stuck in that area when it rotates. It doesn’t smell.

So in this model I see no reason how this will be a problem. It is a sphere and after each visit the whole sphere rotates to clean it up.

Yes, this can be a problem with some models. Make sure you have high back walls or a completely closed toilet to prevent urine leakage.