Does anyone know how to sign for JWT token in OIC if the payload is dynamic?

Summary:

I am trying to obtain a JWT token in OIC, and I followed the instructions here: https://docs.oracle.com/en/cloud/paas/application-integration/rest-adapter/invoke-service-api-jwt-assertion.html#GUID-CFCC30F4-41D8-435B-AD3D-99B5097F4CD2

However, this requires a static payload. My expiration parameter in my payload is always changing as it is only valid for 5 minutes.

Does anyone know how to achieve this with a dynamic payload? I am hoping for some way to do this in integration itself versus through the connection as the above link mentioned, but I am open for any solutions.

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