Does enabling the Integration Runtime service and creating an OAuth client for API usage in Integrat

[misukyoka]

Hello SAP Community,
I am using Integration Suite under a TDD (Test & Development) license.
To call APIs, I need to enable the Integration Runtime service and create an OAuth client.
If I create and actually use these APIs, will there be any additional charges beyond the Integration Suite entitlement?
Also, in the Discovery Center, I can find Integration Suite, but when I search for Integration Runtime service, it does not appear. Is this expected?
(Reference: Discovery Center search link　https://discovery-center.cloud.sap/servicessearch/Integration)

Attached is a screenshot from the Subaccount → Add Service Plans screen, where I see SAP Process Integration Runtime with plans like api and integration-flow.
Any clarification on licensing and cost implications would be greatly appreciated.
Thank you!