Recipe:

{
  "type": "minecraft:crafting_shaped",
  "pattern": [
    "c",
    "r"
  ],
  "key": {
    "c": "minecraft:heavy_core",
    "r": "minecraft:lightning_rod"
  },
  "result": {
    "id": "minecraft:mace",
    "count": 1,
    "components": {
      "minecraft:item_name": "Copper Mace",
      "minecraft:custom_model_data": { "floats": [10] },
      "minecraft:custom_data": {
        "copper_mace_charge": 0
      }
    }
  }
}


Item Modifier:

[
    {
        "function": "minecraft:set_custom_model_data",
        "value": 14
    },
    {
        "function": "minecraft:set_custom_data",
        "tag": "{\"copper_mace_charge\":4}"
    }
]


Item:

{
    "model": {
      "type": "minecraft:range_dispatch",
      "property": "minecraft:custom_model_data",
      "entries": [
        {
          "threshold": 10,
          "model": {
            "type": "minecraft:model",
            "model": "copper_mace:item/copper_mace"
          }
        },
        {
            "threshold": 11,
            "model": {
              "type": "minecraft:model",
              "model": "copper_mace:item/copper_mace_charged_1"
            }
        },
        {
            "threshold": 12,
            "model": {
              "type": "minecraft:model",
              "model": "copper_mace:item/copper_mace_charged_2"
            }
        },
        {
        "threshold": 13,
        "model": {
            "type": "minecraft:model",
            "model": "copper_mace:item/copper_mace_charged_3"
        }
        },
        {
        "threshold": 14,
        "model": {
            "type": "minecraft:model",
            "model": "copper_mace:item/copper_mace_charged_4"
        }
        }
      ],
      "fallback": {
        "type": "minecraft:model",
        "model": "minecraft:item/mace"
      }
    }
}

Item previously:

{
  "parent": "minecraft:item/handheld_mace",
  "textures": {
    "layer0": "minecraft:item/mace"
  },
  "overrides": [
    { "predicate": { "custom_model_data": 10 }, "model": "copper_mace:item/copper_mace" },
    { "predicate": { "custom_model_data": 11 }, "model": "copper_mace:item/copper_mace_charged_1" },
    { "predicate": { "custom_model_data": 12 }, "model": "copper_mace:item/copper_mace_charged_2" },
    { "predicate": { "custom_model_data": 13 }, "model": "copper_mace:item/copper_mace_charged_3" },
    { "predicate": { "custom_model_data": 14 }, "model": "copper_mace:item/copper_mace_charged_4" }
  ]
}