As per Google's documentation:
https://cloud.google.com/storage/docs/aws-simple-migration
GCS bucket can be made to appear from the client's perspective as S3 bucket.
I did everything Google suggested in that page, and configured the following env variables before starting roapi:
AWS_ACCESS_KEY_ID=...
AWS_SECRET_ACCESS_KEY=...
AWS_ENDPOINT_URL="storage.googleapis.com" ( tried with "https://" too)

Still, what I get is

Error: DataFusion error: IO error: No such file or directory (os error 2)

Caused by:
    IO error: No such file or directory (os error 2)

File is definitely there. Is there something else that I can try ?
PS I see GCS integration is on the roadmap, just trying to find an easy way in between.