There is no such thing as a region of a GCP project.
In other words, region/location is specific to resources, and a GCP project is not permanently tied to a single region/location.
For example, you can have a project with multiple BigQuery datasets in different regions.
That same project can have many Compute Engine instances running, each one in different location/region.
There is a default region that is set per GCP project, but that can always be overwritten when creating resources in GCP, and is mainly used to guess default location when location is not specified in API calls.