How do I create a JWK from PFX certificate? - .net-core-3.1

Question

Background: I'm trying to create a JWK from a PFX file so that I'm able to use the Okta SDK.
The OktaClient expects the private key in the form of a JWK. An example I stole from their unit tests looks like.
{
"p": "{{lots_of_characters}}",
"kty": "RSA",
"q": "{{lots_of_characters}}",
"d": "{{lots_of_characters}}",
"e": "AQAB",
"kid": "3d3062f5-16a4-42b5-837b-19b6ef1a0edc",
"qi": "{{lots_of_characters}}",
"dp": "{{lots_of_characters}}",
"dq": "{{lots_of_characters}}",
"n": "{{lots_of_characters}}"
}
Everything I've tried results in the exception "Something went wrong when creating the signed JWT. Verify your private key." I believe this is because I'm losing the private key part of the cert when I use the IdentityModel convert method (noted below).
var signingCert = new X509Certificate2("{{my_cert}}.pfx", "{{my_passphrase}}");
var privateKey = signingCert.GetRSAPrivateKey();
var rsaSecurityKey = new RsaSecurityKey(privateKey);
// The "HasPrivateKey" flag is suddenly false on the resulting object from this method
var rsaJwk = JsonWebKeyConvert.ConvertFromRSASecurityKey(rsaSecurityKey);
var rsaJwkSerialized = JsonSerializer.Serialize(rsaJwk);
var oktaClientConfig = new OktaClientConfiguration
{
OktaDomain = "{{my_okta_domain}}",
ClientId = {{my_client_id}},
AuthorizationMode = AuthorizationMode.PrivateKey,
PrivateKey = new JsonWebKeyConfiguration(rsaJwkSerialized);,
Scopes = new List<string> {"okta.users.manage"}
};
var oktaClient = new OktaClient(oktaClientConfig);
// This throws when trying to self-sign the JWT using my private key
var oktaUsers = await oktaClient.Users.ListUsers().ToArrayAsync();

Answer 1

Well, after days of trying to figure this out, found it mere hours after finally posting on SO.
It turns out there are flags you set when you create the X509Certificate2 that can tell the cert that it is exportable and this is required for the JsonWebKeyConverter to properly create the JWK.
var signingCert = new X509Certificate2("{{my_cert}}.pfx", "{{my_passphrase}}", X509KeyStorageFlags.Exportable);