FABRIC PORT IS NOT george8188625's MOD! It would be amazing if you would keep this here for those with the same issue. I understand that it is not your project on fabric though. However, this is the repo that shows up when searching and the person responsible for the port is not active on this project.

Create Diesel Generators Fabric - 2.1.3
Create Fabric - v0.5.1d (Sodium & Create compatible version for MC-1.20.1)

Engine Piston Recipe:
    "Q# ",
    "#G ",
    "  S"
Key:
    "#"
      "tag": "c:plates/iron"
    "Q"
      "item": "create:andesite_alloy"
    "G"
      "item": "create:shaft"
    "S"
      "tag": "c:nuggets/zinc"

When browsing the recipe, only create:andesite_alloy and create:shaft are shown in REI/JEI.
ISSUES

• MC-1.20.1 Create Fabric-v0.5.1d uses #c:zinc_nuggets instead of the forge tag format of #c:nuggets/zinc shown in the recipe
• MC-1.20.1 Create Fabric-v0.5.1d uses #c:iron_plates instead of the forge tag format of #c:plates/iron shown in the recipe
• MC-1.20.1 Create Fabric-v0.5.1d uses #c:brass_plates instead of the forge tag format of #c:plates/brass shown in the recipe

SOLUTION

• Added create:iron_sheet to tag #c:plates/iron using datpack
• Added create:brass_sheet to tag #c:plates/brass using datpack
• Added create:zinc_nugget to tag #c:nuggets/zinc using datapack

data/c/tags/items/plates/iron.json

{
    "replace": false,
    "values": [
      "create:iron_sheet"
    ]
  }

data/c/tags/items/plates/brass.json

{
    "replace": false,
    "values": [
      "create:brass_sheet"
    ]
  }

data/c/tags/items/nuggets/zinc.json

{
    "replace": false,
    "values": [
      "create:zinc_nugget"
    ]
  }