I need help figuring out shields custom model data 1.21.5

I modified some code from a resource pack that adds custom shields, and then made it so the shield would use my Custom Model Data, but the custom model is not showing up. Pls help!
{
  "model": {
    "type": "minecraft:select",
    "property": "minecraft:component",
    "component": "minecraft:custom_name",
    "cases": [
      {
        "when": "redstone_sheath",
        "model": {
          "type": "minecraft:condition",
          "on_false": { "type": "minecraft:model", "model": "minecraft:item/redstone_sheath" },
          "on_true": { "type": "minecraft:model", "model": "minecraft:item/redstone_sheath_blocking" },
          "property": "minecraft:using_item"
        }
      }
    ],
    "fallback": {
      "type": "minecraft:condition",
      "on_false": {
        "type": "minecraft:special",
        "base": "minecraft:item/shield",
        "model": { "type": "minecraft:shield" }
      },
      "on_true": {
        "type": "minecraft:special",
        "base": "minecraft:item/shield_blocking",
        "model": { "type": "minecraft:shield" }
      },
      "property": "minecraft:using_item"
    }
  }
}