Unable to access SharePoint Web using PnPCore SDK

Question

I can connect to a SharePoint Online Web using the PnP Framework, but am unable to do so using PnP SDK Core using the same app registration and certificate.

What am I doing wrong?

Here is my PnP Framework code:

var clientId = "..";
var tenantId = "..";
var siteUrl = "..";
X509Certificate2 certificate = GetKeyVaultCertificate(vaultName, certificateName); 
var authManager = AuthenticationManager.CreateWithCertificate(clientId, certificate, tenantId);
using (var context = await authManager.GetContextAsync(siteUrl))
{
    var web = context.Web;
    context.Load(web, w => w.Id, w => w.Title);
    await context.ExecuteQueryAsync();
    Console.WriteLine($"{web.Id} - {web.Title}");
}

Here is my PnP SDK Code:

var clientId = "..";
var tenantId = "..";
var siteUrl = "..";
var certificate = GetKeyVaultCertificate(vaultName, certificateName);
var host = Host.CreateDefaultBuilder()
.ConfigureServices((hostingContext, services) =>
{
    services.AddPnPCore(options =>
    {
        options.Sites.Add("DefaultSite", new PnPCoreSiteOptions
        {
            SiteUrl = siteUrl
        });
    });
    services.AddPnPCoreAuthentication( options =>
    {
        options.Credentials.Configurations.Add("x509certificate", new PnPCoreAuthenticationCredentialConfigurationOptions
        {
            ClientId = clientId,
            TenantId = tenantId,
            X509Certificate = new PnPCoreAuthenticationX509CertificateOptions
            {
                Certificate = certificate
            }
        });
        options.Credentials.DefaultConfiguration = "x509certificate";
        options.Sites.Add("DefaultSite", new PnPCoreAuthenticationSiteOptions
        {
            AuthenticationProviderName = "x509certificate"
        });
    });
})
.UseConsoleLifetime()
.Build();

await host.StartAsync();

using (var scope = host.Services.CreateScope())
{
    var pnpContextFactory = scope.ServiceProvider.GetRequiredService<IPnPContextFactory>();
    using (var context = await pnpContextFactory.CreateAsync("BccSite"))
    {
        var web = await context.Web.GetAsync(p => p.Title);
        Console.WriteLine($"Title: {web.Title}");
    }
}
host.Dispose();

The exception occurs on the GetAsync line:

PnP.Core.MicrosoftGraphServiceException
    HResult=0x80131500
    Message=Microsoft Graph service exception