UiPath GSuite Activity: Google service account role

Hi, I have a question about service account roles when using Gsuite activities with service accounts

We have created a robot that sends Gmail using Uipath’s Gsuite activity.

When we use GSuite API with UiPath, we are considering using Service Account instead of OAuth. In this case, the role assigned to Service Account is minimized in terms of security. I understand at least that the owner role is bad. Can you advise what kind of roll is good? Or you can link to it.
I’m sorry because it might be a question of GCP…

Best Regards.