Blazor Server Entity Framework Core: data column encryption not working

I'm trying to make my user data more secure by encrypting sensitive data like Firstname and Lastname of a client. But when I use the following code from medium and update my database, the data doesn't get encrypted after adding an new client.

Source:
https://medium.com/emrekizildas/encrypt-your-database-columns-with-entityframework-1f129b19bdf8

Other suggestions for encrypting data are also welcome!

These are the things I tried:

• Updating from .NET Core 3.1 to .NET 5.0 and changing package version
• Creating 128bit key instead of "test123456"
• AesEncryption: https://github.com/Eastrall/EntityFrameworkCore.DataEncryption

Model/DbContext:

using EntityFrameworkCore.EncryptColumn;
using EntityFrameworkCore.EncryptColumn.Extension;
using EntityFrameworkCore.EncryptColumn.Interfaces;
using EntityFrameworkCore.EncryptColumn.Util;
using Globals.Entities;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;
using System;

private readonly IEncryptionProvider _provider;

public Model()
{
    Initialize.EncryptionKey = "test123456";
    this._provider = new GenerateEncryptionProvider();
}

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.UseEncryption(this._provider);
}

Example entity:

using EntityFrameworkCore.EncryptColumn.Attribute;

namespace Globals.Entities
{
    public class Client
    {
        [Key]
        [Required]
        public int Id { get; set; }

        [EncryptColumn]
        public string FirstName { get; set; }

        [EncryptColumn]
        public string LastName { get; set; }

        public Client(string firstName, string lastName)
        {
            FirstName = firstName;
            LastName = lastName;
        }
    }
}

Commands for reinstalling the database:

drop-database
remove-migration
add-migration initialCreate
update-database