Thank you for asking this question on the **Microsoft Q&A Platform. **
The role will depend on the activity that the user performs, for example, to create a new workspace you will require the role owner or contributor at the Resource group-level. (If you receive a failure when trying to create a workspace for the first time, make sure that your role allows Microsoft.MachineLearningServices/register/action. This action allows you to register the Azure Machine Learning resource provider with your Azure subscription.)
You can get more information about RBAC for Azure Machine Learning workspace here
Hope this helps!
Accept Answer and Upvote, if any of the above helped, this thread can help others in the community looking for remediation for similar issues.
NOTE: To answer you as quickly as possible, please mention me in your reply.