How I can save in a Excel file using c# only the links of the pages that are with Status 404

Question

The application I am working on must take every link saved in an excel and run it, and in case the page status is 404, I have to save each link in a new excel (by that I mean in a excel to be all, not each link in a separate excel). So far I've managed to get every link to run, as well as create a new excel in case I manage to make it work, but unfortunately I'm stuck at this point where I don't know how or what to write in the code for save every time the status is 404 after checking the URLs in the existing Excel

using System;
using System.Collections.Generic;
using System.IO;
using System.Net.Http;
using System.Threading.Tasks;
using Microsoft.Office.Interop.Excel;
using OfficeOpenXml;

namespace StartaproUrls
{
 partial class Program
 {
    private static int statusCode;
    private static HttpResponseMessage result;
    private static object[,] valueArray;
    static async Task Main(string[] args)
    {
        using var client = new HttpClient();

        

        string path = @"C:\Users\stefanv\Downloads\startapro_urls.xlsx";
        Application excelApp = new();

        if (excelApp != null)
        {
            Workbook excelWorkbook = excelApp.Workbooks.Open(path);
            Worksheet excelWorksheet = (Worksheet)excelWorkbook.Sheets[1];

            Microsoft.Office.Interop.Excel.Range excelRange = excelWorksheet.UsedRange;
            int rowCount = excelRange.Rows.Count;
            int colCount = excelRange.Columns.Count;

            valueArray = (object[,])excelRange.get_Value(
                        XlRangeValueDataType.xlRangeValueDefault);

            for (int i = 1; i <= 20; i++)
            {
                for (int j = 1; j <= colCount; j++)
                {
                    
                    result = await client.SendAsync(new HttpRequestMessage(HttpMethod.Head, $"https://beta.startapro.hu{valueArray[i, j]}"));
                    statusCode = (int)result.StatusCode;
                    Console.WriteLine(statusCode);  // or result

                } 
            }

            excelWorkbook.Close();
            excelApp.Quit();
        }

        ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
        var file = new FileInfo(@"C:\Users\stefanv\Downloads\startapro_urlsError.xlsx");

        var urlError = GetSetupData();
        await CreateExcelForErrorUrls.SaveExcelFile(urlError, file);
    }


    public static List<UrlErrorModel> GetSetupData()
    {
        List<UrlErrorModel> output = new()
        {
            new() { UrlWithError = valueArray }
        };

        return output;
    }
  }
}

Bellow is the class for creating the Excel

using OfficeOpenXml;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using static StartaproUrls.Program;

namespace StartaproUrls
 {
  class CreateExcelForErrorUrls
  {
    public static async Task SaveExcelFile(List<UrlErrorModel> urlError, FileInfo file)
    {
        DeleteIFExists(file);

        using var package = new ExcelPackage(file);

        var ws = package.Workbook.Worksheets.Add("ErrorRaport");

        var range = ws.Cells["A1"].LoadFromCollection(urlError, true);
        range.AutoFitColumns();

        await package.SaveAsync();

    }

    private static void DeleteIFExists(FileInfo file)
    {
        if (file.Exists)
        {
            file.Delete();
        }
    }
   }
 }

And Bellow is the Model for UrlError

namespace StartaproUrls
 {
  partial class Program
   {
    public class UrlErrorModel
    {
        public object UrlWithError { get; set; }
    }
  }
}