MongoDB Aggregation - Accessing lookup fields in project - mongodb

Question

I access a lookup field in $project using $unwind but this breaks the accessibility of the other nested fields from the main collection. Is there any way to access the fields from both collections in $project. I thought of merging the arrays but still not sure if it's the right approach.
Users collection
{
"_id" : ObjectId("5a54f739fe0a00373e7ef1e8"),
"team" : {
"name" : "test",
},
"updated_at" : ISODate("2018-05-22T04:28:00Z"),
"created_at" : ISODate("2018-01-09T17:09:13Z"),
"users" : [
{
"updated_at" : ISODate("2018-11-22T11:55:22Z"),
"created_at" : ISODate("2018-01-09T17:09:13Z"),
"_id" : ObjectId("5a54f739fe0a00373e7ef1e9"),
"name" : test,
"status" : "active",
"title" : "Engineer",
},
{
"updated_at" : ISODate("2018-11-22T11:55:22Z"),
"created_at" : ISODate("2018-01-09T17:09:13Z"),
"_id" : ObjectId("5a54f739fe0a00373e7ef1e9"),
"name" : test1,
"status" : "passive",
"title" : "Tester",
}
]
}
Comments collection:
{
"_id" : ObjectId("6062178fc73fe806e45c9b69"),
"userId" : "5a54f739fe0a00373e7ef1e9",
'text' : 'this is a test',
"status" : "1",
"timestamp" : ISODate("2021-03-29T18:08:14.317Z")
}
Pipeline
$pipeline = [['$match' => [
'users' => [
'$elemMatch' => [
'field1' => $field1,
],
]
]
],
['$unwind' => '$users'],
['$match' => [
'users.field1' => $field1,
]
],
['$addFields' => ['userId' => ['$toString' => '$userId' ]]],
['$lookup' => [
'from' => 'comments',
'localField' => 'userId',
'foreignField' => 'userId',
'as' => 'userComments'
]
],
['$unwind' => '$userComments'],
['$project' => [
'comments' => [
'$switch' => [
'branches' => [
[ 'case' => [
'$eq' => ['$userComments.status','verified']
],
'then' => 1],
[ 'case' => [
'$lte' => ['$userComments.status', '']
],
'then' => 1],
],
'default' => 0
]
],
'status' => '$users.status',
'total' => [false],
]
],
['$group' => [
'_id' => $groupBy,
'text' => ['$sum' => '$comments'],
'total' => ['$sum' => '$total'],
'completed' => ['$sum' => '$status'],
]
],
];
result
{"_id" :"categories","text": 21,"total": 100,"completed":50}