Describe the solution you'd like
A keyword like "strict_override" = true for datapack files such that they completely replace any other version of the file lower in the datapacks priority.

Why is this feature needed
Right now, to ensure you override all the settings in the default configs, you have to fill in all the values of the default config and set them to a default value. Ex: This biome overwrite https://pastebin.com/tSGkssCY

So with a strict_override it would look like:

{
    "strict_override":true
}

This is what vanilla's datapack filters already do. You can use /pmmo genData disabler to have a pack automatically created to disable lower data.

This disabler pack only has a pack.mcmeta with filters which you can cut/paste to your own pack or use as reference. This specific filter disables all lower priority pmmo data, however, you can add specific filters to only disable things like biomes while leaving the rest intact.

Oh! Didn't know about that one. Perfect!