Hi! Thank you so much for replying to my post. I really appreciate the different rugs that you recommended for me. I'll try to describe what my legs and my feet like to stand on, but it's tricky because it is so particular. The surface needs to be cushioned, but it can't be spongy or anything like memory foam or something your feet can really sink into. Anything textured is a no. I can stand on a carpet barefoot, as long as the carpet isn't super plush. I think the examples that you sent me wouldn't work.
What I might try next in the bathroom is instead of folding the towel into a square for me to stand on, I will try just folding it in half and see how that feels.
Again, thank you so much for the suggestions and I really appreciate the help people have been giving me.