Render a variable from input JSON into Step Function non-path supported variable

I am trying to make the following spec work for setting up a Dataset Import. I am passing in an input JSON as shown below. The keys with .$ JSONPath support are able to read the values from the input JSON.

However, I am unable to pass in a value from the input JSON into S3 object which does not seem to support the Path.$, and Path itself does not render the JSONPath structure.

How do I populate Path within the S3Config to read from the input JSON?

"Import-Forecast-Dataset": {
      "Type": "Task",
      "Parameters": {
        "DatasetImportJobName.$": "$.ProjectName",
        "DatasetArn.$": "$.createDatasetResult.DatasetArn",
        "DataSource": {
          "S3Config": {
            "Path": "$.S3Path",
            "RoleArn": "arn:aws:iam::XXXXXXXXXXXXX"
          }
        },
        "TimestampFormat": "yyyy-MM-dd"
      },
      "Resource": "arn:aws:states:::aws-sdk:forecast:createDatasetImportJob",
      "Next": "Create-DatasetGroup",
      "ResultPath": "$.createDatasetImportJobResult"
    }

input JSON:

{
"ProjectName": "A",
"S3Path": "s3://somepath"
}