Remove Swimming Datapack

Hiya I'm trying to make a survival island smp where you can't really leave by removing boat crafts, and making it so that you can't swim in water (just like back when you only drowned in water) and you can only jump out but cant escape the island. If anyone could give me any clues to start/point me in the direction of an already existing datapack, keep in mind i've only ever done 1 recipe datapack before so...