API Connect has a managed service offering call API Connect Reserved Instance. This uses the OIDC user registry provided by IBM Cloud to provide access.

When logging in via the API Connect CLI to an instance using ODIC requires a the user getting token, normally this is done by a pop up asking for authorization. However with a headless setup a pop up is not convenient. Ricky Moorhouse has written this great article on how to handle this with an OIDC registry on IBM Cloud.

https://rickymoorhouse.uk/blog/2021/cicd-workaround/