Can't update variant image with new file using productSet mutation

[Vuong_Dac]

Hi, i’m having trouble updating product with new file in variant using productSet mutation,
for example, this is my ProductSetInput:

{
        "id": "gid://shopify/Product/7574574497931",
        "title": "Winter hat",
        "productOptions": [
            {
                "name": "Color",
                "position": 1,
                "values": [
                    {
                        "name": "Grey"
                    },
                    {
                        "name": "Black"
                    }
                ]
            }
        ],
        "files": [
            {
                "id": "gid://shopify/MediaImage/27697075847307"
            },
            {
                "id": "gid://shopify/MediaImage/27697075880075"
            },
            {
                "originalSource": "https://example.com/foo.jpg",
                "contentType": "IMAGE"
            }
        ],
        "variants": [
            {
                "optionValues": [
                    {
                        "optionName": "Color",
                        "name": "Grey"
                    }
                ],
                "file": {
                    "id": "gid://shopify/MediaImage/27697075880075"
                },
                "price": 11.99
            },
            {
                "optionValues": [
                    {
                        "optionName": "Color",
                        "name": "Black"
                    }
                ],
                "file": {
                    "originalSource": "https://example.com/foo.jpg",
                    "contentType": "IMAGE"
                },
                "price": 11.99
            }
        ]
  }

if i reading the example in the docs correctly, my variant should be updated with new media, but instead, only the media is uploaded but not my variant and there was no error
Can someone help me out on this, what am i doing wrong here?