Deploy a Cloud Function for each step that calls the corresponding downstream system to complete the required action.

Create a Pub/Sub topic for each step. Create a subscription for each downstream development team to subscribe to their step's topic.

Create a Pub/Sub topic for timesheet submissions. Create a subscription for each downstream development team to subscribe to the topic.

Create a timesheet microservice deployed to Google Kubernetes Engine. The microservice calls each downstream step and waits for a successful response before calling the next step.