Look what just showed up in the Microsoft 365 Admin Center for GCC customers:
Here’s the message text from https://portal.office.com/adminportal/home?ref=MessageCenter/:/messages/MC256836:
Whiteboard for GCC
MC256836 · Published May 17, 2021
Message Summary
Whiteboard for web and Teams meetings will become available for your tenant.
Note: The new Whiteboard experience requires OneDrive for Business. If your organization does not have OneDrive for Business, please verify that Whiteboard is disabled.
When this will happen
Starting in mid June and completing by mid-July.
How this will affect your organization
Your end users can create and collaborate on whiteboards in the web application and in Teams meetings.
Whiteboard will begin a gradual roll-out in GCC. The data is stored in OneDrive for Business and Whiteboard is on by default but can be disabled using the SharePoint admin PowerShell cmdlets. The supported features allow you to create and collaborate on whiteboards using the web application and within a Teams meeting. It does not yet include native applications on Windows 10, Surface Hub or iOS.
Note: If you have a Surface Hub, the Whiteboard application will continue to operate in a local-only mode and cannot collaborate with the service. We will be adding support for the native applications later in 2021, another announcement will be shared as we have more details.
What you need to do to prepare
If you do not wish to have this service available, you can disable it using the SharePoint Online PowerShell module following the instructions in the Additional Information.
If you do not have OneDrive for Business, you should verify that Whiteboard is disabled using the SharePoint Online PowerShell module.