Generate jwt token using external system key

1. Current setup

we are generating the JWT token using and external system key and the details we are stored in the Third-party credentials in Appian admin console, and we are using the JWT token to generate the token, and this approach works well.

2. Problem

The external system key expires every six months. This requires manual updates to the key in the third-party credentials in the admin console.

We have access to a Realtime API to retrieve the external system key dynamically. Is there a way to generate the JWT token without manually updating the third-party credentials every six months

I need to build like this, I have a process first I will trigger the API to get the external system key and I will pass the key and i have to get the JWT token.