How to select all values of query based dropdown widget inside $aggregate and $match

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1

I have a query which gives the result in single column

{
“collection”: “Orders”,
“aggregate”: [
{
“$project”: {
XYZ : 1,
“source.platform” :1
}
},

    {
        "$lookup": {
            "from": "users",
            "localField": "XYZ",
            "foreignField": "_id",
            "as": "salesRepInfo"
        }
    },
   
    {
        "$project": {
            "_id": 0,
            "SalesRep Name": "$salesRepInfo.name",
            "sourceplatform" : "$payments.source.platform"
            }
        },
        {
            "$match": {
              "sourceplatform":{"$in":["APP"]}
        }
        },
        
        {
"$group": {
	"_id":{"SalesRep Name":"$SalesRep Name"}
                 }
        }
]

}

I want to use the result of this query in another query as query based dropdown list inside $match operator. first query gives more than 100 outputs, i want to select all in the second query. How can I do that?

2

@jesse it would be great if you can please help?