Programmatically extracting a file over 1GB using 7 zip is too slow or hangs in between

Trying to extract files over 1 GB using 7zip library. Code in c#. When trying to extract manually it works well, bit through c# code it takes longer or sometimes even hangs.

Below code I’m using

     string arg = $"x -y -mx=1 -mmt=off <zipfile> -o<Outputpath>";
     string sevenzip = @"<path_to_7zip>7z.exe";
                    
     Process p = new Process()
     {
        StartInfo = new ProcessStartInfo()
        {
           FileName = sevenzip,
           Arguments = arg,
           UseShellExecute = false,
           RedirectStandardOutput = true,
           RedirectStandardError = true,
           WindowStyle = ProcessWindowStyle.Hidden,
           CreateNoWindow = true
        }
     };
 
     p.Start();
     string outputUnicode = null; 
     int exitCode=0;
     CancellationToken token = default(CancellationToken);
     GetProcessOutputWithTimeout(p, 7200000, token, out outputUnicode, out exitCode);

        public void GetProcessOutputWithTimeout(Process process, int timeoutSec, CancellationToken token, out string output, out int exitCode)
        {
            string outputLocal = ""; 
            int localExitCode = -1;
            var task = System.Threading.Tasks.Task.Factory.StartNew(() =>
            {
                outputLocal = process.StandardOutput.ReadToEnd();
                process.WaitForExit();
                localExitCode = process.ExitCode;
            }, token);

            if (task.Wait(timeoutSec, token))
            {
                output = outputLocal;
                exitCode = localExitCode;
            }
            else
            {
                exitCode = -1;
                output = "";
            }
            if (process.HasExited == false)
            {
                process.Kill();
            }
            process.Close();
        }

This code works well with smaller files but larger files takes more than 2 hours. I have kept timeout of 2 hours, because I don’t want it to hang in between.
Tried every possible way but no luck. Not sure what I’m doing wrong.