Entity Framework Core - maneira eficiente de atualizar Entity que tem filhos com base na representação JSON da entidade que está sendo passada via Web API

var existingCustomer = await loyalty.Customer
    .Include(c => c.ContactInformation)
    .Include(c => c.Address)
    .Include(c => c.MarketingPreferences)
    .Include(c => c.ContentTypePreferences)
    .Include(c => c.ExternalCards)
    .FirstOrDefault(c => c.McaId == customer.McaId);

if (existingCustomer == null)
{
    // Customer does not exist, insert new one
    loyalty.Add(customer);
}
else
{
    // Customer exists, replace its property values
    loyalty.Entry(existingCustomer).CurrentValues.SetValues(customer);

    // Insert or update customer addresses
    foreach (var address in customer.Address)
    {
        var existingAddress = existingCustomer.Address.FirstOrDefault(a => a.AddressId == address.AddressId);

        if (existingAddress == null)
        {
            // Address does not exist, insert new one
            existingCustomer.Address.Add(address);
        }
        else
        {
            // Address exists, replace its property values
            loyalty.Entry(existingAddress).CurrentValues.SetValues(address);
        }
    }

    // Remove addresses not present in the updated customer
    foreach (var address in existingCustomer.Address)
    {
        if (!customer.Address.Any(a => a.AddressId == address.AddressId))
        {
            loyalty.Remove(address);
        }
    }
}

loyalty.SaveChanges();