Problem Slow PartialView rendering speed in ASP.NET MVC C#

Question

I get a number of items through the web service and display them to the user in the form of Json through Jquery, the problem here is that I get the desired number of items very quickly from the desired web service, but when I want the desired items show it to the user, it takes a long time to render it.The number of desired items is 100 items.

Response Class:

public class ApiResponse
{
     public List<ApiQuestion> Questions { get; set; }
     public string RenderToHtml { get; set; }
     public string Message { get;set; }
}
public class ApiQuestion
{
     public int Row { get; set; }
     public string Text { get; set; }
}

Method for Get Item:

[HttpPost]
public async Task<ActionResult> PartialQuestionDetail(ApiGetQuestionDetailRequest request)
{
     try
     {
           //**The desired result is taken from the web service and put in the **result** variable**//


           //The display speed in this section is low
           result.RenderToHtml = WebController.RenderRazorPartialViewToString(
                    WebController.CreateController<DashboardPartialController>().ControllerContext,
                    "~/_PartialQuestionDetail.cshtml",
                    result.Questions);
           result.Message = "OK";

           return Json(result);
     }
     catch (Exception ex)
     {
           return Json(new PostQuestionDetail
           {
              Message = "ERROR"
           });
     }
}

Function RenderRazorPartialViewToString

public static string RenderRazorPartialViewToString(ControllerContext context, string fullPathPartialView,
            object model = null, bool partial = true)
        {
            // first find the ViewEngine for this view
            ViewEngineResult viewEngineResult = null;
            if (partial)
                viewEngineResult = ViewEngines.Engines.FindPartialView(context, fullPathPartialView);
            else
                viewEngineResult = ViewEngines.Engines.FindView(context, fullPathPartialView, null);

            if (viewEngineResult == null)
                throw new FileNotFoundException("View cannot be found.");

            // get the view and attach the model to view data
            var view = viewEngineResult.View;
            context.Controller.ViewData.Model = model;

            string result = null;

            using (var sw = new StringWriter())
            {
                var ctx = new ViewContext(context, view, context.Controller.ViewData, context.Controller.TempData, sw);
                view.Render(ctx, sw);
                result = sw.ToString();
            }

            return result;
        }

Function CreateController:

public static T CreateController<T>(RouteData routeData = null) where T : Controller, new()
        {
            // create a disconnected controller instance
            T controller = new T();

            // get context wrapper from HttpContext if available
            HttpContextBase wrapper;
            if (System.Web.HttpContext.Current != null)
                wrapper = new HttpContextWrapper(System.Web.HttpContext.Current);
            else
                throw new InvalidOperationException(
                    "Cannot create Controller Context if no active HttpContext instance is available.");

            if (routeData == null)
                routeData = new RouteData();

            // add the controller routing if not existing
            if (!routeData.Values.ContainsKey("controller") &&
                !routeData.Values.ContainsKey("Controller"))
                routeData.Values.Add("controller", controller.GetType().Name.ToLower().Replace("controller", ""));

            controller.ControllerContext = new ControllerContext(wrapper, routeData, controller);
            return controller;
        }

_PartialQuestionDetail.csHtml:

<table class="table custom-table m-0">
  <thead>
       @{
@*The number of desired items is 100 items.*@
              foreach (var item in Model.Response.Questions ?? new List<ApiQuestion>())
              {
                     
                   <tr>
                        <th>
                            <label>@Html.Raw(item.Text)</label>
                        </th>
                    </tr>
 }
  </thead>
</table>

Jquery:

function loadQuestionDetail() {
            
            const formData = new FormData();
            formData.append('request.QuestionSubjectId', ****);

            var xmlHttpRequest = new XMLHttpRequest();
            if (!window.XMLHttpRequest) {
                xmlHttpRequest = new ActiveXObject("Microsoft.XMLHTTP");
            }

            xmlHttpRequest.open(
                "POST",
                '@Url.Action("PartialQuestionDetail", "***", new {area = "***"})',
                true);

            xmlHttpRequest.onerror = function() {
                window.$('#layoutMain').html(ShowLayoutError(ERROR_TEXT));
            };

            xmlHttpRequest.onloadend = function() {
                var response = ParseJson(xmlHttpRequest.responseText);

                switch (response.Message) {
                case "ERROR":
                    window.$('#layoutMain').html(ShowLayoutError(response.Message));
                    return;
                }

                window.$('#layoutMain').html(response.RenderToHtml);
                
                
            }
            xmlHttpRequest.send(formData);
        }

In general, the problem here is that the information is obtained very quickly through the web service, but when it goes to the Render section, it takes a long time to display the desired items to the user, for this, Json is used, which contains other data along with the desired item I also want to receive it, that's why it is done in Json in the server part