Csharp 哪个 TPL 最适合 .NET API 中的这种情况任务线程

我有一个方法，可以在观看视频时增加观看的点击量. 如果发布者的视频点击量达到200次，我会给他发一封祝贺邮箱， 但如果邮箱发送延迟，我不希望用户等待延迟才观看视频. 我需要使视频加载不依赖于邮箱发送. 我使用过Task.Run和Task.Factory.StartNew和Inside It Parallell 我没有使用任务/线程的经验，所以哪种方法是实现它的最佳方式.

public async Task<ServiceResponse<ViewedVideoDto>> AddVideoView(int candidateVideoId)
        {
            var video = await _dbcontext.CandidateFiles.Include(x=>x.Candidate).ThenInclude(x=>x.User).FirstOrDefaultAsync(x => x.Id == candidateVideoId);
            if (video is null)
            {
                return new ServiceResponse<ViewedVideoDto>().NotFound(nameof(Resource.VideoEmpty), Resource.VideoEmpty);
            }
            video.VideoViews += 1;
            _dbcontext.Update(video);
            await _dbcontext.SaveChangesAsync();
            if (video.VideoViews == 200)
            {
                //Method 1 
                await Task.Run(() =>
                   _candidateEmailService.Achieved200VideoViews(video.Candidate.User.Email,
                       video.Candidate.User.FullName));

                //Method 2
                   Task.Factory.StartNew(() => Parallel.Invoke(() =>
                  {
                      _candidateEmailService.Achieved200VideoViews(video.Candidate.User.Email,
                          video.Candidate.User.FullName);
                  }));
                  
            }
            return new ServiceResponse<ViewedVideoDto>()
            {
                Data = new ViewedVideoDto()
                {
                    VideoId = video.Id
                }
            };
            

        }

 public async Task Achieved200VideoViews(string receiverEmail, string fullName)
    {
        var candidateTemplate = EmailTemplate.Return(EmailTemplateConst.CanEmailTempFolder, EmailTemplateConst.CanAchieved200VideoViews,fullName);
            
        var innoEmail = new InnoEmail()
        {
            Email = receiverEmail,
            Subject = "Touchpoint after 200 views",
            HtmlMessage = candidateTemplate 
        };
        await _emailService.SendAsync(innoEmail);

public async Task<bool> SendAsync(Email email)
        {
            try
            {
                var apiKey = _configuration.GetSection("SENDGRID_API_KEY").GetSection("SecretKey").Value;
                var Email = _configuration.GetSection("SENDGRID_API_KEY").GetSection("Email").Value;

                var client = new SendGridClient(apiKey);
                var msg = new SendGridMessage()
                {
                    From = new EmailAddress(Email, "test"),
                    Subject = email.Subject,
                    PlainTextContent = null,
                    HtmlContent = email.HtmlMessage
                };
                msg.AddTo(new EmailAddress(email.Email));

                var response = await client.SendEmailAsync(msg).ConfigureAwait(false);

                response.StatusCode.ToString();
                return true;
            }
            catch (System.Exception e)
            {
                return false;
            }
        }