World Gen Small Islands

I want to make a datapack that generates a world with small islands around 50-100 blocks, that are seperate from each other 50 to 100 blocks as well and a big ocean that can vary from deep ocean, warm ocean, and all the other oceans. I've been looking a bit into how to make world generation and I'm wondering if the better approach is to override the overworld dimension with the one big .json file and change all the paramters to my liking or some other way that is easier? Would I need to change every biome's settings for this to work or could I just change the oceans settings? Thanks in advance!