Enchantment effects conditions

Hello, I'm in MC 1.21.1, trying to make an armor enchantment effect that prevents fireworks damage if the original source of damage is the entity wearing the enchantment
I'm not sure whether this is possible at all, I can just not do this, but it would have been cool to have this handled by the vanilla enchantment system without special casing it myself.
here's what I got so far:
  "effects": {
    "minecraft:damage_immunity": [
      {
        "requirements": {
          "condition": "minecraft:damage_source_properties",
          "predicate": {
            "direct_entity": {
              "type": "minecraft:firework_rocket"
            },
            "is_direct": false,
            "source_entity": {
              // not sure what to put here
            },
            "tags": [
              {
                "expected": true,
                "id": "fireworkfrenzy:is_firework" // tag that just contains firework damage
              }
            ]
          }
        }
      }
    ]
  }