Error CS0234

using Microsoft.Data.SqlClient;

namespace DataAccessLibrary
{
    public class SqlDataAccess
    {
        private readonly IConfiguration _config;

        public string ConnectionStringName { get; set; } = "Default";

        public SqlDataAccess(IConfiguration configuration)
        {
            _config = configuration;
        }

        public async Task<List<T>> LoadData<T, U>(string sql, U parameters) 
        {
            string connectionString = _config.GetConnectionString(ConnectionStringName);

            using(IDbConnection connection = new Microsoft.Data.SqlClient.SqlConnection(connectionString))
            {

            }

            return null;
        }
    }
}

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

  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Dapper" Version="2.1.35" />
    <PackageReference Include="Microsoft.Data.SqlClient" Version="5.2.0" />
  </ItemGroup>

</Project>