Quero mesclar células e fazê-lo várias vezes ... A razão pela qual estou usando essa mesclagem é porque quero mais a tabela. e um número diferente de colunas para cada tabela e tamanho diferente de uma coluna na outra ... O número e os locais das mesclagens são desconhecidos

    using Microsoft.Office.Interop.Excel;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp111
{
    class Program
    {
        static void Main(string[] args)
        {
            string x = @"C:\Users\hed-b\source\repos\TESTUserFormFromExcel\ConsoleApp111\bin\Debug\TEST.xltm";

            Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.Application
            {
                DisplayAlerts = false,
                Visible = false,
                ScreenUpdating = false,
            };

            Workbook wb = xlApp.Workbooks.Open(x);
            Worksheet ws = (Worksheet)wb.Worksheets[1];
            if (ws == null)
            {
                Console.WriteLine("Worksheet could not be created. Check that your office installation and project references are correct.");
                return;
            }
            Stopwatch stopWatch = Stopwatch.StartNew();

            for (int i = 2; i <= 10; i++)
            {
                ws.get_Range("A"+i, "B"+i).Merge();

            }
            for (int i = 2; i <= 10; i++)
            {
                ws.get_Range("C" + i, "D" + i).Merge();
            }
            for (int i = 2; i <= 10; i++)
            {
                ws.get_Range("E" + i, "H" + i).Merge();
            }
            Console.WriteLine(stopWatch.ElapsedMilliseconds);

            stopWatch = Stopwatch.StartNew();
            ws.get_Range("A" + 2, "H" + 10).Value2 = new string[10, 5]{
                { "aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
                { "aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
                { "aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
                { "aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
                { "aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
                { "aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
                { "aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
                { "aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
                { "aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
                { "aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"},
            };

            ws.get_Range("A" + 11, "H" + 15).Value2 = new string[5, 8]{
                { "bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb"},
                { "bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb"},
                { "bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb"},
                { "bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb"},
                { "bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb","bbbbb"}
            };

            Console.WriteLine(stopWatch.ElapsedMilliseconds);

            xlApp.ScreenUpdating = true;
            xlApp.Visible = true;
        }
    }
}

Eu só estou procurando uma maneira melhor de fazer isso mais rápido

Todas essas mesclas de programas de exemplo levam cerca de 1724 ms. no meu programa atual, tenho muito mais mesclagens e levo mais de 5000 ms. Isso mescla o que leva a maior parte do tempo ...