Unable to generate ExtentReport for .NetCore App 2.1?

I am working on .NetCore App 2.1 project and I created some selenium scripts in C# for that project with NUnit framework(in MacOS). I am able to execute it successfully. However, I am not able to generate report using Extent Report 3.1.3(Also, Tried 2.41.x), As I am getting warning that It has been restored with .NETFramework 4.6.1, But not with .NetCore app with Project Target framework, while compilinh. When I execute it, It threw me lots of exception. I resolved one by one, by adding Nuget packages. Finally, I am into the following exception, from which I am not able to move further.

TearDown failed for test fixture RBAutomationDemo.UnitTest1
TearDown : System.TypeLoadException : Could not load type 'System.Security.Principal.WindowsImpersonationContext' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.
--TearDown
 at RazorEngine.Compilation.DirectCompilerServiceBase.CompileType_Windows(TypeContext context)
at RazorEngine.Templating.RazorEngineCore.CreateTemplateType(ITemplateSource 
razorTemplate, Type modelType)
  at RazorEngine.Templating.RazorEngineCore.Compile(ITemplateKey key, Type modelType)
  at RazorEngine.Templating.RazorEngineService.CompileAndCacheInternal(ITemplateKey key, Type modelType)
  at RazorEngine.Templating.RazorEngineService.GetCompiledTemplate(ITemplateKey key, Type modelType, Boolean compileOnCacheMiss)
  at RazorEngine.Templating.RazorEngineService.RunCompile(ITemplateKey key, TextWriter writer, Type modelType, Object model, DynamicViewBag viewBag)
  at RazorEngine.Templating.RazorEngineServiceExtensions.WithWriter(Action`1 withWriter)
  at AventStack.ExtentReports.Reporter.ExtentHtmlReporter.Flush()
  at AventStack.ExtentReports.Model.Report.<>c.<NotifyReporters>b__29_1(IExtentReporter x)
  at System.Collections.Generic.List`1.ForEach(Action`1 action)
  at AventStack.ExtentReports.Model.Report.NotifyReporters()
  at AventStack.ExtentReports.Model.Report.Flush()
  at AventStack.ExtentReports.ExtentReports.Flush()
  at RBAutomationDemo.UnitTest1.OneTimeTearDown()`

Please help me on this.

1. Is that possible to use Extent Reports in .NetCore 2.1(in MacOS)? if so Please provide me steps to achieve it.
2. If Extent Reports not compatible with .NetCore app 2.1, Please suggest better reporting tool as alternative(pref. open-source)
3. I am going to CI it in VSTS. Will reporting be really needed for this scenario separately?

Code I used:

using System;
using AventStack.ExtentReports;
using AventStack.ExtentReports.Reporter;
using LocatorsFile;
using NUnit.Framework;
using NUnit.Framework.Interfaces;

namespace RBAutomationDemo
{
    [SetUpFixture]
    public abstract class Base
    {
    protected ExtentReports _extent;
    protected new ExtentTest _test;

    [OneTimeSetUp]
    protected void ReportSetup()
    {
        var dir = TestContext.CurrentContext.TestDirectory + "\\";
        var fileName = this.GetType().ToString() + ".html";
        System.Console.WriteLine(fileName);
        ExtentHtmlReporter htmlReporter = new ExtentHtmlReporter(dir + fileName);

        _extent = new ExtentReports();
        _extent.AttachReporter(htmlReporter);
    }

    [OneTimeTearDown]
    protected void ReportTearDown()
    {
        _extent.Flush();
    }



    [SetUp]
    public void BeforeTest()
    {
        _test = _extent.CreateTest(TestContext.CurrentContext.Test.Name);
        Initialize();
    }

    [Test]
    public void Testmethod1()
    {
        _test = extent.CreateTest("Checking Total workbooks count");

        try
        {
            _test.Pass("Assertion passed");
            _test.Log(Status.Pass, "Pass");
        }
        catch
        {
            _test.Fail("Assertion failed");
            _test.Log(Status.Fail, "Fail");
            throw;
        }

    }


    [TearDown]
    public void AfterTest()
    {
        var status = TestContext.CurrentContext.Result.Outcome.Status;
        var stacktrace = string.IsNullOrEmpty(TestContext.CurrentContext.Result.StackTrace)
                ? ""
                : string.Format("{0}", TestContext.CurrentContext.Result.StackTrace);
        Status logstatus;

        switch (status)
        {
            case TestStatus.Failed:
                logstatus = Status.Fail;
                break;
            case TestStatus.Inconclusive:
                logstatus = Status.Warning;
                break;
            case TestStatus.Skipped:
                logstatus = Status.Skip;
                break;
            default:
                logstatus = Status.Pass;
                break;
        }

        _test.Log(logstatus, "Test ended with " + logstatus + stacktrace);
        _extent.Flush();
        DoTearDown();
    }
}
}