I just ran into a similar rabbit hole. This helped me with out any other .dll installs. Hope this helps someone.
using System.Text.Json.Nodes;
public static string cSettings = AppDomain.CurrentDomain.BaseDirectory + @"\Application_Settings.json";
public static void Read_JSON() 
{
   string read = File.ReadAllText(cSettings);
   var jsonObject = JsonNode.Parse(read);
   var appname = jsonObject["appname"];
   MessageBox.Show(appname.ToString());
}
//output: my test app
Application_Settings.json
{
  "appname": "my test app",
  "version": "1.0.003",
  "id": null,
  "firstrun": null,
  "firstname": "t",
  "lastname": "t",
  "email": "some@gmail.com",
  "cpu1id": "F00A20F10",
  "cpu1key": null,
  "gamingpc": false
}
Link to where I found this reference.
I'm using Visual Studio 2022 C#