format arbitrary JSON string with System.Text.Json

FormatJsonString.cs

string json = """
{ "X": 123, "Y": { "Y1": 1, "Y2": 2 } }
""";
JsonSerializerOptions options = new(JsonSerializerDefaults.General) { WriteIndented = true };
string formatted = JsonSerializer.Serialize(JsonSerializer.Deserialize<JsonElement>(json), options);
Console.WriteLine(formatted);
/* output: 
{
  "X": 123,
  "Y": {
    "Y1": 1,
    "Y2": 2
  }
}
*/