Hi,
I don't think the DevTest lab will go anywhere soon, it recently (May 27, 2020) got generally available in Azure Government and Switzerland regions.
You'll find the Azure roadmaps over here:
Azure DevOps Feature Timeline
https://learn.microsoft.com/en-us/azure/devops/release-notes/features-timeline
Azure updates
https://azure.microsoft.com/en-us/updates/
Best regards,
Leon