According to the docs, a default service account is used to manage and execute dataform in GCP.
Is there a way to use another service account instead ?
You can now change service accounts in GCP Dataform.
You have two options, the project service account and workflow config service accounts.
The project service account can be either set in the Create Repository dialogue:
Or via the Settings tab in the project itself:
Workflow config service accounts can be edited in the create / edit dialogue for individual workflow configs: