You have to be careful using the UI vs CLI/Terraform as you will get inconsistent results. For example, enabling any API via the UI will also create any "glue"

You have to be careful using the UI vs CLI/Terraform as you will get inconsistent results. For example, enabling any API via the UI will also create any "glue" service accounts in your project that are expected for that API to operate (for example, Compute API and the default compute service account). If you were to enable the Compute API via Terraform, it will NOT create the default compute service account -- you will need to do that with a separate terraform resource. There are tons of quirks related to operating GCP but not significantly moreso than other cloud providers.