You can stay in the grand beach hotel on surfside and there are restaurants who do Friday night meals. I am not sore about Shabbos day. Some people go to a shul for a kiddush or buy and it on
The hotel room
If you have time/patience to buy your own food I'd recommend that.
There are one or two places in Miami where you can prepay your meal and eat but I didn't personally have fantastic experience with that.