Cannot load System.Web.HttpContext error with razor pages and WebMail

Question

I've been having trouble getting WebMail to work sending an email using a contact form using This Official Microsoft Tutorial. My current issue is that I'm getting the error:

Could not load type 'System.Web.HttpContext' from assembly 'System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.

After searching online I'm finding a lot of answers saying that I simply cant use System.Web, HttpContext, or add the necessary assemblies which I find hard to believe considering I have it set up exactly as the tutorial provides.Any and all help is greatly appreciated.

My usings:

@using System.Web;
@using System.Web.Helpers;

My code which runs after submitting my form:

@{
     ViewData["Title"] = "Email Confirmation";

            var clientEmail = Request.Form["clientEmail"];
            var clientName = Request.Form["clientName"];
            var clientPhone = Request.Form["clientPhone"];
            var clientMessage = Request.Form["clientMessage"];
            var errorMessage = "";
            var debuggingFlag = false;
            try
            {
                // Initialize WebMail helper
                WebMail.SmtpServer = "smtp.myserver.com";
                WebMail.SmtpPort = 587;
                WebMail.UserName = "MYEMAIL";
                WebMail.Password = "MYPASSWORD";
                WebMail.From = "MYEMAIL";
                WebMail.EnableSsl = true;


                // Send email
                WebMail.Send(to: "MYEMAIL",
                    subject: $"Message from {clientName}",
                    body: $"{clientMessage}\nPhone: {clientPhone}\nEmail: {clientEmail}"
                );
            }
            catch (Exception ex)
            {
                errorMessage = ex.Message;
            }
}

EDIT I've also tried adding the System.Web.dll assembly but I'm getting the message that The reference is invalid or unsupported Here is my csproj if it helps:

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
    <RootNamespace>MYRAZORSITE</RootNamespace>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="bootstrap" Version="5.1.3" />
    <PackageReference Include="Microsoft.AspNet.WebPages" Version="3.2.8" />
  </ItemGroup>

</Project>