I make the assumption that my island is in a rather warm climate so I don't need to hurry that much about building something house-like.
Anyways, I would make sure that I have internet on my island somehow.
I would prepare myself beforehand to figure out how to survive in such a climate. As I totally have no experience, I want internet so I can still connect to the rest of the world. Somehow I would like electricity as well, as my device to access the Internet would need power supply.
Than I would just try to live there for a year and see if I like it or not. It seems nice but on the other hand, being alone for a full year without accommodation, not sure if I would effectively enjoy it for my whole life. Re-evaluate after a year, if I like it, I'll stay there. If I don't like it, I can go on holidays to my island to 'deconnect'.
If it would end up to be totally not my thing, put it for sale and invest the money in such a way that I have a passive income stream.