2 questions: After you created vpc peering in GCP should not it send a auto request to GCP for approval ? 2.Do we need to create any routes after peering is done?
You may want to look into PrivateLink if you need multiple GCP projects connecting to one Atlas project. As for defining the CIDR of an Atlas project, if you use the API or Terraform you can create a new project and define the details of the network container to be created. I have the github linked in that specific terraform video if you want to take a closer look.