How can I make a smithing table recipe that yields a named item?

I am trying to make a datapack where you can combine a turtle shell and a netherite ingot in a smithing table to get a turtle shell with knockback resistance and armor toughness. I have figured out the whole smithing table situation, but I cannot get it to yield an item with attributes. Here is a snip of what it looks like in the smithing table and a snip of the code.

{ "type": "minecraft:smithing", "base": { "item": "minecraft:turtle_helmet" }, "addition": { "item": "minecraft:netherite_ingot" }, "result": { "item": "minecraft:turtle_helmet" } }
}