Inline data vs Index for Vega visualization

Newbie using OpenSearch, I believe version 2.3.
Trying to use Vega(v5) or Vega-Lite(v4) to create a visualization but finding that I can only get it to work when embedding data in the visualization. When switching this over to use an Index, the results just show ‘undefined’.
I am sure this is just a simple thing due to not understanding how to format the Vega logic when using the index but have tried and cannot figure it out.

Using vega with embedded data 
{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "description": "A simple bar chart with embedded data.",
  "background": "white",
  "padding": 5,
  "autosize":"fit-x",
   "title": {
    "text": ["Managers Rating Distribution", "Showing % of total rating"],
    "frame": "group"
  },
  "style": "cell",
  "data": [
    {
      "name": "source_0",
      "values": [
        {
          "Documents": 1,
          "Manager": "Rosanna Channing",
          "Review Rating": "Meets Expectations"
        },
        {
          "Documents": 1,
          "Manager": "Rosanna Channing",
          "Review Rating": "Meets Expectations"
        },
        {
          "Documents": 1,
          "Manager": "Rosanna Channing",
          "Review Rating": "Meets Expectations"
        },
        {
          "Documents": 1,
          "Manager": "Rosanna Channing",
          "Review Rating": "Meets Expectations"
        },
        {
          "Documents": 1,
          "Manager": "Rosanna Channing",
          "Review Rating": "Meets Expectations"
        },
        {
          "Documents": 1,
          "Manager": "Rosanna Channing",
          "Review Rating": "Company Maker"
        },
** more rows... removed for readability **
        {
          "Documents": 1,
          "Manager": "Netty Owyang",
          "Review Rating": "Unsatisfactory"
        },
        {"Documents": 1, "Manager": "Netty Owyang", "Review Rating": "No Value"}
      ]
    },
    {
      "name": "data_1",
      "source": "source_0",
      "transform": [
        {
          "type": "aggregate",
          "groupby": ["Manager", "Review Rating"],
          "ops": ["sum"],
          "fields": ["Documents"],
          "as": ["sum_Documents"]
        },
        {
          "type": "stack",
          "groupby": ["Manager"],
          "field": "sum_Documents",
          "sort": {"field": ["Review Rating"], "order": ["ascending"]},
          "as": ["sum_Documents_start", "sum_Documents_end"],
          "offset": "normalize"
        },
        {
          "type": "filter",
          "expr": "isValid(datum[\"sum_Documents\"]) && isFinite(+datum[\"sum_Documents\"])"
        }
      ]
    },
    {
      "name": "data_2",
      "source": "source_0",
      "transform": [
        {
          "type": "joinaggregate",
          "as": ["total"],
          "ops": ["sum"],
          "fields": ["Documents"],
          "groupby": ["Manager"]
        },
        {
          "type": "formula",
          "expr": "datum.Documents / datum.total",
          "as": "percentage"
        },
        {
          "type": "aggregate",
          "groupby": ["Manager", "Review Rating"],
          "ops": ["sum", "sum"],
          "fields": ["Documents", "percentage"],
          "as": ["sum_Documents", "sum_percentage"]
        },
        {
          "type": "stack",
          "groupby": ["Manager"],
          "field": "sum_Documents",
          "sort": {"field": ["Review Rating"], "order": ["ascending"]},
          "as": ["sum_Documents_start", "sum_Documents_end"],
          "offset": "normalize"
        },
        {
          "type": "filter",
          "expr": "isValid(datum[\"sum_Documents\"]) && isFinite(+datum[\"sum_Documents\"])"
        }
      ]
    }
  ],
  "signals": [
    {"name": "y_step", "value": 50},
    {
      "name": "height",
      "update": "bandspace(domain('y').length, 0.1, 0.05) * y_step"
    }
  ],
  "marks": [
    {
      "name": "layer_0_marks",
      "type": "rect",
      "style": ["bar"],
      "from": {"data": "data_1"},
      "encode": {
        "update": {
          "fill": {"scale": "layer_0_color", "field": "Review Rating"},
          "ariaRoleDescription": {"value": "bar"},
          "description": {
            "signal": "\"Sum of Documents: \" + (format(datum[\"sum_Documents_end\"]-datum[\"sum_Documents_start\"], \".0%\")) + \"; Manager: \" + (isValid(datum[\"Manager\"]) ? datum[\"Manager\"] : \"\"+datum[\"Manager\"]) + \"; Review Rating: \" + (isValid(datum[\"Review Rating\"]) ? datum[\"Review Rating\"] : \"\"+datum[\"Review Rating\"])"
          },
          "x": {"scale": "x", "field": "sum_Documents_end"},
          "x2": {"scale": "x", "field": "sum_Documents_start"},
          "y": {"scale": "y", "field": "Manager"},
          "height": {"signal": "max(0.25, bandwidth('y'))"}
        }
      }
    },
    {
      "name": "layer_1_marks",
      "type": "text",
      "style": ["text"],
      "from": {"data": "data_2"},
      "encode": {
        "update": {
          "dx": {"value": -15},
          "dy": {"value": 0},
          "fill": {"scale": "layer_1_color", "field": "Review Rating"},
          "description": {
            "signal": "\"Percentage: \" + (format(datum[\"sum_Documents_end\"]-datum[\"sum_Documents_start\"], \".0%\")) + \"; Manager: \" + (isValid(datum[\"Manager\"]) ? datum[\"Manager\"] : \"\"+datum[\"Manager\"]) + \"; Review Rating: \" + (isValid(datum[\"Review Rating\"]) ? datum[\"Review Rating\"] : \"\"+datum[\"Review Rating\"]) + \"; Sum of percentage: \" + (format(datum[\"sum_percentage\"], \".0%\"))"
          },
          "x": {"scale": "x", "field": "sum_Documents_end"},
          "y": {"scale": "y", "field": "Manager", "band": 0.5},
          "text": {"signal": "format(datum[\"sum_percentage\"], \".0%\")"},
          "align": {"value": "center"},
          "baseline": {"value": "middle"}
        }
      }
    }
  ],
  "scales": [
    {
      "name": "x",
      "type": "linear",
      "domain": [0, 1],
      "range": [0, {"signal": "width"}],
      "nice": true,
      "zero": true
    },
    {
      "name": "y",
      "type": "band",
      "domain": {
        "fields": [
          {"data": "data_1", "field": "Manager"},
          {"data": "data_2", "field": "Manager"}
        ],
        "sort": true
      },
      "range": {"step": {"signal": "y_step"}},
      "paddingInner": 0.1,
      "paddingOuter": 0.05
    },
    {
      "name": "layer_0_color",
      "type": "ordinal",
      "domain": {"data": "data_1", "field": "Review Rating", "sort": true},
      "range": "category"
    },
    {
      "name": "layer_1_color",
      "type": "ordinal",
      "domain": {"data": "data_2", "field": "Review Rating", "sort": true},
      "range": ["white"]
    }
  ],
  "axes": [
    {
      "scale": "x",
      "orient": "bottom",
      "gridScale": "y",
      "grid": true,
      "tickCount": {"signal": "ceil(width/40)"},
      "domain": false,
      "labels": false,
      "aria": false,
      "maxExtent": 0,
      "minExtent": 0,
      "ticks": false,
      "zindex": 0
    },
    {
      "scale": "x",
      "orient": "bottom",
      "grid": false,
      "title": "Percentage",
      "format": ".0%",
      "labelFlush": true,
      "labelOverlap": true,
      "tickCount": {"signal": "ceil(width/40)"},
      "zindex": 0
    },
    {
      "scale": "y",
      "orient": "left",
      "grid": false,
      "title": "Manager",
      "zindex": 0
    }
  ],
  "legends": [
    {"fill": "layer_0_color", "symbolType": "square", "title": "Review Rating"}
  ]
}

I can produce this visualization

When I try to switch this to use our index, I just get an Undefined result.

{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "description": "Manager Rating distribution by percent.",
  "background": "white",
  "padding": 5,
  "autosize":"fit-x",
   "title": {
    "text": ["Managers Rating Distribution", "Showing % of total rating"],
    "frame": "group"
  },
  "style": "cell",
  "data": [
    {
      "name": "source_0",
      "url":{ "index":"hc_ep_perf_ratings_mgr*" }

    },
    {
      "name": "data_1",
      "source": "source_0",
      "transform": [
        {
          "type": "aggregate",
          "groupby": ["Manager", "Review Rating"],
          "ops": ["sum"],
          "fields": ["Document ID"],
          "as": ["sum_Documents"]
        },
        {
          "type": "stack",
          "groupby": ["Manager"],
          "field": "sum_Documents",
          "sort": {"field": ["Review Rating"], "order": ["ascending"]},
          "as": ["sum_Documents_start", "sum_Documents_end"],
          "offset": "normalize"
        },
        {
          "type": "filter",
          "expr": "isValid(datum[\"sum_Documents\"]) && isFinite(+datum[\"sum_Documents\"])"
        }
      ]
    },
    {
      "name": "data_2",
      "source": "source_0",
      "transform": [
        {
          "type": "joinaggregate",
          "as": ["total"],
          "ops": ["sum"],
          "fields": ["Document ID"],
          "groupby": ["Manager"]
        },
        {
          "type": "formula",
          "expr": "datum.Documents / datum.total",
          "as": "percentage"
        },
        {
          "type": "aggregate",
          "groupby": ["Manager", "Review Rating"],
          "ops": ["sum", "sum"],
          "fields": ["Document ID", "percentage"],
          "as": ["sum_Documents", "sum_percentage"]
        },
        {
          "type": "stack",
          "groupby": ["Manager"],
          "field": "sum_Documents",
          "sort": {"field": ["Review Rating"], "order": ["ascending"]},
          "as": ["sum_Documents_start", "sum_Documents_end"],
          "offset": "normalize"
        },
        {
          "type": "filter",
          "expr": "isValid(datum[\"sum_Documents\"]) && isFinite(+datum[\"sum_Documents\"])"
        }
      ]
    }
  ],
  "signals": [
    {"name": "y_step", "value": 50},
    {
      "name": "height",
      "update": "bandspace(domain('y').length, 0.1, 0.05) * y_step"
    }
  ],

etc. Rest remains the same as before.

The index does have the “Manager” field and the “Review Rating” field. I was trying to update the visualization to not need the Documents:1 by changing to use a “count” aggregation instead of “sum” but it didnt make a difference.