There is another option. I just found out about this one so no personal experience but on another travel forum people have been using it and are very happy. It’s called Airalo. It’s an app that you can download on your smart phone. Then you purchase a country or region specific data package. They do have SXM. You will then have a data service from the local cell provider but you will not be able to make a voice calls unless using another apps like FaceTime or WhatsApp. So it’s basically like having the island wide wifi all the time and not only at the free wifi spots like bars and restaurants.
I will be giving this app a try in a few months. Apparently, there are a few other similar apps available.