Designing a GraphQL schema for an analytics platform

I'm just starting to explorer GraphQL as an option for my analytic platform API layer.

My UI is mainly built from tables and charts. most of the times the data represents some DB columns grouped by a dimension.

I've found the following article https://www.microsoft.com/developerblog/2017/09/28/data-independent-graphql-using-view-model-based-schemas/ from Microsoft, describing their take on how suck GraphQL schemas should be designed (see below).

type Query {
  channels(source: String!, query:String!, appId:String!, apiKey:String!): [Channel]
  lineCharts(source: String!, query:String!, appId:String!, apiKey:String!, filterKey:String, filterValues:[String]): [LineChart]
  pieCharts(source: String!, query:String!, appId:String!, apiKey:String!): [PieChart]
  barCharts(source: String!, query:String!, appId:String!, apiKey:String!, filterKey:String, filterValues:[String]): [BarChart]
}

type Channel {
  name: String
  id: Int
}

type LineChart {
  id: String
  seriesData : [Series]
}

type PieChart {
  id: String
  labels: [String]
  values: [Int]
}

type BarChart {
  id: String
  seriesData : [Series]
}

type Series {
  label: String
  x_values: [String]
  y_values: [Int]
}

It seems to me that this design is strict, forcing any new chart to be added to the root Query. How can the schema be more generic, without loosing GraphQL benefits?