Hierarchical queries with Mongo using $graphLookup able to process three level but required multiple level

Question

the answer provided in below link works for 2 levels of Hierarchy, i am trying to achieve multiple levels of Hierarchy but not working

answer

The result should be like,

          10     ->>> Manager
          /\
         /  \
        8    6  ---->> 8 & 6 reporting to manager 10
        /\    /\
       /  \  /  \
      4    5 2   1  ---->> 4 & 5 reporting to manager 8 ...
     /      /
    /      /
   3      7         ---->> 3 reporting to manager 4 ...
         /
        /
       11          ---->> 11 reporting to manager 7 ...

Sample Data :-

db.getCollection("employees").insert({"_id":"10","empId": "10","name":"Employee10","managerId":"15" });

db.getCollection("employees").insert({"_id":"8","empId": "8","name":"Employee8","managerId":"10" });

db.getCollection("employees").insert({"_id":"6","empId": "6","name":"Employee6","managerId":"10" });

db.getCollection("employees").insert({"_id":"4","empId": "4","name":"Employee4","managerId":"8" });

db.getCollection("employees").insert({"_id":"5","empId": "5","name":"Employee5","managerId":"8" });

db.getCollection("employees").insert({"_id":"2","empId": "2","name":"Employee2","managerId":"6" });

db.getCollection("employees").insert({"_id":"1","empId": "1","name":"Employee1","managerId":"6" });

db.getCollection("employees").insert({"_id":"3","empId": "3","name":"Employee3","managerId":"4" });

db.getCollection("employees").insert({"_id":"7","empId": "7","name":"Employee7","managerId":"2" });

db.getCollection("employees").insert({"_id":"11","empId": "11","name":"Employee11","managerId":"7" });

Query i have tried from the given answer by some one the below query which i have tried from the above link but only able to achieve three level after that not able to add more graphlookup if i try to add another level, i am getting not nested data

db.employees.aggregate([
{
    $match: {
        empId : "10"
    }
},
// level 0
{
   $graphLookup: {
      from: "employees",
      startWith: "$empId",
      connectFromField: "empId",
      connectToField: "managerId",
      as: "reportees",
      maxDepth: 0
   }
},
{
    $unwind: "$reportees" // flatten
},
{
    $addFields: {
        "reportees.level": 0 // add level field
    }
},
// level 1
{
   $graphLookup: {
      from: "employees",
      startWith: "$reportees.empId",
      connectFromField: "reportees.empId",
      connectToField: "managerId",
      as: "reportees.reportees",
      maxDepth: 0
   }
},
 // **if i add another graphLookup i am getting all are flattened**  // need to add multiple level
{
    $group: { // group previously flattened documents back together
        _id: "$_id",
        empId: { $first: "$empId" },
        name: { $first: "$name" },
        managerId: { $first: "$managerId" },
        reportees: { $push: "$reportees" },
    }
},
{
    $addFields: {
        "reportees.reportees.level": 1 // add level field
    }
}
])