Can't query-filter or get node with a Int64 id

There is something weird going on with my Int64 GraphQL queries.
A general query works as expected, but when using getInventory or queryInventory with a filter, it doesn’t work. A filter with ‘greater than’ and a value with fewer digits works, however.
My GraphQL playground has the docs so getInventory is definitely there and I get no errors from the query. Does this have something to do with Int64? Why haven’t I found similar issues from other people on the forum? I’ve used the get operation with other values before, so it must be working.

Hope someone can help.

Here is my schema:

type Inventory {
  steamID64: Int64! @id
}

Here is the simple query with it’s output. This is working as expected.

query QueryInvs {
  queryInventory {
    steamID64
  }
}

Output data (my 17 digit id, blurred it here of course):

"data": {
    "queryInventory": [
      {
        "steamID64": 765xxxxx11355xxxx
      }
    ]
  }

However, this query returns null:

query GetInv {
  getInventory(steamID64: 765xxxxx11355xxxx) {
    steamID64
  }
}

Output:

{
  "data": {
    "getInventory": null
  },
  "extensions": {
    "tracing": {
      "version": 1,
      "startTime": "2022-04-18T20:50:16.483005902Z",
      "endTime": "2022-04-18T20:50:16.488195592Z",
      "duration": 5189711,
      "execution": {
        "resolvers": [
          {
            "path": [
              "getInventory"
            ],
            "parentType": "Query",
            "fieldName": "getInventory",
            "returnType": "Inventory",
            "startOffset": 665592,
            "duration": 4508960,
            "dgraph": [
              {
                "label": "query",
                "startOffset": 922073,
                "duration": 4248563
              }
            ]
          }
        ]
      }
    }
  }
}