The Microsoft Dynamics 365 2019 Release Wave 2 is not available for early adopters. The release is scheduled to start deployment to production environments starting in October of 2019. During August and September, Microsoft Dynamics customers check out the upcoming list of updates that will be released in October.
Recently I had to work on a PowerApps/Flow solution that would connect to a Dynamics 365 data source. I have done various things previously with the Dynamics 365 connector, but when trying to do the same in my GCC environment, I could not see the Dynamics 365 connector. I thought it was removed, but then I checked my commercial environment and it was there.