Failed to install .apks (not apk) using Appium in C# on real android device

I am trying to install apks file on real device using Appium in C# as part of automation script. When I ran appium-doctor , it shows bundletool.jar is installed at:.<detailed path of bundle-tool,i.e. under Android/Sdk/ bundletool> Below is my code:
using NUnit.Framework;
using OpenQA.Selenium;
using OpenQA.Selenium.Appium;
using OpenQA.Selenium.Appium.Android;
using OpenQA.Selenium.Remote;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AppiumTest
{
 
public class TestCase
{
    AndroidDriver<AndroidElement> driver;
    AppiumOptions options;
    String appPath = "C:\\APK\\my-app-app.apks";
    

    [SetUp]
    public void InitDriver()
    {
        options = new AppiumOptions();
        
        options.AddAdditionalCapability("platformName","Android");
        options.AddAdditionalCapability("platformVersion", "8.1.0");
        options.AddAdditionalCapability("deviceName", "Device-Name");
        options.AddAdditionalCapability("udid", "XB127009");
        options.AddAdditionalCapability("app", appPath);
        
        Uri url = new Uri("http://127.0.0.1:4723/wd/hub");
        Console.WriteLine("Starting!!!");
        driver = new AndroidDriver<AndroidElement>(url, options);
        driver.InstallApp(appPath);
        
        Console.WriteLine("Finish");
            
    }

    [Test]
    public void openApp()
    {
        Assert.IsNotNull(driver);
        System.Threading.Thread.Sleep(2000);
    }

    [TearDown]
    public void closeApp()
    {
        driver.Quit();
    }

}
}

When I run the test, below error shows: An unknown server-side error occurred while processing the command. Original error: bundletool.jar binary is expected to be present in PATH. Visit https://github.com/google/bundletool for more details.
Does appium does not support installation of apks file and support only apk file ? because in the Appium documentation, it states support Android App Bundle: http://appium.io/docs/en/writing-running-appium/android/android-appbundle/

Any help is much appreciated.