Service account doesn't show up in Google Play Console after creation

I had the same problem, I fixed it this way:

When you create a service account in step 2, you need to select a role to grant this service account some permissions, although it shows the step is optional, but for some cases, it's not. If you skip this step, the newly created service account will not show up at the Google Play Console API access page, and you will get this error message, The current user has insufficient permissions to perform the requested operation when you run your code.

You much enable "Google Play Android Developer API" (one of Google Api & services) for your application via a credential!Google supplies many API for developers can call them from their app. A credential same as a permit (3 types of credentials : API key (such as youtube), OAuth, Service Account)If you never enable one API, it never shown on API Access page!

In my case:Even if you have created a service account,When you have already deleted the service account with the same name,It appears to have been deleted from the IAM tab of Google Cloud Platform.So it is assumed that it is not visible in the play console.

TODO:Create a service account with a different name (I gave the owner permission in step2 when creating, Like Q Locker's answer.).After creation, it was immediately exposed in the play console.