Any way to make an Ocean world generation but with one and only one island at spawn?

Hi guys, I'm pretty new here. But I've been trying to make my own datapack lately (with no succsess) and I would ask for some help. Other than helping websites and already existing codes, I'm not really good with datapacks. I recently found a few solutions to make an ocean only world with every structures included. But I wonder if it was possible to make the same world generation, but with an actuall overworld generated island in the middle of the world, with every possible biome, to make it into a fun surival experience. I know that it is possible to generation islands spread widely in the world, but would it be possible for only one to generate?