i know we can use American express to buy any thing from amazon but why not from amazon via paypal here is a recent article that i read on this topic https://www.withintheflow.com/dropshipping/amazon-paypal/
Not only paypal but also amazon not allow to take any sort of transaction witch is related to sexual products in fact amazon not contain such a this kind of products and as per my knowledge amazon is not supporting paypal any for gettign transaction using his platform.