According to https://docs.aws.amazon.com/cognito/latest/developerguide/saml-identity-provider.html#role-customization-saml it should be possible to let gsuite as saml provider passthrough a role-arn via an attribute to a cognito setup.
But it does not really specify how? I added the attribute https://docs.aws.amazon.com/cognito/latest/developerguide/saml-identity-provider.html#role-customization-saml
on gsuite but obviously that alone does not work.