Datapack for a mod

I was trying to implement some of my custom content into Brewin' and Chewin' mod keg recipes. But I stumbled upon a problem, that my custom item didn't display similar to the item on the left.
I searched inside mod's files, and found a .json file inside assets folder. And wrote this based on it:
{
  "minecraft:water": {
    "id": "minecraft:potion",
    "tag": {
      "Potion": "minecraft:water"
    }
  },
"kubejs:torchflower_wine": "kubejs:torchflower_wine",
  "create:potion": {
    "id": "minecraft:potion",
    "tag": {
      "Potion": {
        "brewinandchewin:fluid_tag": "Potion"
      }
    },
    "optional": true
  },
  "create:tea": {
    "id": "create:builders_tea",
    "optional": true
  }
}

Put it in datapack. It should theoretically work, but it doesn't, sadly. And I feel kinda stuck
The directory of .json file is 
assets/brewinandchewin/brewinandchewin/fluid_item_displays/default_displays.json