Thank you for posting this in Microsoft Q&A.
As I understand you want to know if RBAC transition will affect on-premises installs of Azure DevOps server.
The transition to RBAC will not affect on-premises installations of Azure DevOps Server. RBAC simply involves various roles with multiple permissions that are integral to Azure.
Performing RBAC transitions will not impact Azure resources, assuming the necessary permissions and roles are correctly assigned to the required accounts in Azure.
Let us know if you have any further questions.
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