Generate JWT Admin token without SDK in C#

We need to get the admin token in order to issue administative tasks for provisioning users from/to our external system in a generic way. (admin token, not user token)

As the RSA keys will be supplied by the customer we need to sign the token with them.

Looking at the source code of the SDK, i see that it uses Bouncy Castle lib, but we can not use this lib, too.

I couldn't come across a sample on how to that.

I'd appreciate if you anyone can share some sample on how to that with pure .NET using Microsoft.IdentityModel.Tokens.Jwt namespace.

Thank you for reading.