FedRamp applies to the Azure Gov tenants. Qualys is not available for the Gov tenants. https://learn.microsoft.com/en-us/azure/defender-for-cloud/deploy-vulnerability-assessment-vm#availability
I recommend the following link:
https://learn.microsoft.com/en-us/azure/compliance/offerings/offering-fedramp
I also recommend working with your organization's Microsoft support contacts for additional details if needed.