Two APIs have different jobs
The State Machines management API creates environments, returns credentials, and manages snapshots. Your State Machines API key authenticates those calls within a workspace. The app’s native API handles your integration’s work. For Salesforce, that includes record operations, SOQL queries, and supported Bulk and SOAP operations. Credentials identify both the environment and an actor inside the app. Your State Machines API key is never an app credential.Match the starting point to the task
To use the same resources through the UI, follow Run an environment in the dashboard.