Hi there, welcome to the boards
4 months is a bad, bad age for short naps. The boards here are covered with mums of 4 month olds, tearing their hair out over short naps. That is not to say that it is not worth trying to extend them, but you may have to accept that an element of it is developmental and that longer naps are just something she will grow into.
Now I have to tell you that paci weaning is NOT a panacea for short naps. In fact it can make matters worse. I know that when I weaned my LO at the same age, he just carried right on with his short naps, and now I had no way to keep him calm in his cot. It was still worth weaning it, for us, because our nights were so disturbed, and his naps did eventually lengthen out.