Hi Steve and welcome to our abode.
In principle, all of your desires can be satisfied using Wappler, albeit with some manual scripting where it concerns connections to proprietary services. Please be aware that there is no such thing as Wappler hosting; the code that Wappler produces can be hosted anywhere, even from your own system if it is setup to do so.
You make mention of RSS feeds. Although possible, it is ancient technology being XML based. The future is JSON facilitated by using RESTful API’s. This is a huge feature that is incorporated in Wappler. See API Connector components, how to use and connect REST/Curl API's. API’s can be used for payment gateways, FB, Twitter, blogs etc etc etc.
SEO tools are available while security is possibly the best around because of an automatically assigned Site Secret Key.