JS converting nested objects into an array of objects

I have this:

var dataSet = { 
data: {
    department: [
        { 
          "Marketing": [
            { "employee_1": "1210" },
            { "employee_2": "3241" },
            { "employee_3": "6510" },
            { "employee_4": "9510" }

          ]
        },
        { 
          "Sales": [
          { "employee_1": "5210" },
          { "employee_2": "1241" },
          { "employee_3": "8510" },
          { "employee_4": "2510" }
          ]
        },
        { 
          "RD": [
          { "employee_1": "1010" },
          { "employee_2": "9241" },
          { "employee_3": "9430" },
          { "employee_4": "3510" }
          ]
        },
        ...
    ]
}

}

And I need this:

const data = [
          {name: 'Marketing', Low: 2, Medium: 4, High: 3},
          {name: 'Sales', Low: 3, Medium: 1, High: 5},
          {name: 'RD', Low: 6, Medium: 1, High: 2},
          ...
    ];

Where:

LOW     employee_x < 2000 
MEDIUM  employee_x >= 2000 && employee_x < 5000
HIGH    employee_x >= 5000

My last attempt was something like this:

    var low_arr_dept = [];
    var medium_arr_dept = [];
    var high_arr_dept = [];

    for (var i in dataSet.data) {
                var department = departments_data[i];

                        for (var d in department) {
                            var score = department[d];
                            for (var j in score) {

                                if (Object.values(department[d][j]) >= 5000) {
                                    console.log("Object.values(department[d][j]) ", Object.values(department[d][j]))
                                    low_arr_dept.push({

                                        score: Object.values(department[d][j])
                                    });
                                } else if (Object.values(department[d][j]) >= 2000 && Object.values(department[d][j]) < 5000) {
                                    medium_arr_dept.push({

                                        score: Object.values(department[d][j])
                                    });
                                } else if (Object.values(department[d][j])  <2000) {
                                    high_arr_dept.push({

                                        score: Object.values(department[d][j])
                                    });
                                }


                            } 
                        }

            }



            // Creating arrays and then getting their length
            low_arr_dept_marketing.length.toString()
            medium_arr_dept_marketing.length.toString()
            high_arr_dept_marketing.length.toString()

// For creating this:
const data = [
          {name: 'Marketing', Low: low_arr_dept_marketing.length, Medium: medium_arr_dept_marketing.length, High: high_arr_dept_marketing.length},
          {name: 'Sales', Low: low_arr_dept_sales.length, Medium: medium_arr_dept_sales.length, High: high_arr_dept_sales.length},
          {name: 'RD'Low: low_arr_dept_rd.length, Medium: medium_arr_dept_rd.length, High: high_arr_dept_rd.length},
          ...
    ];