In order to manage voice and phone number assignments in Microsoft Teams, you need at least Teams Communications Administrator role. This role does however have more privileges than most organizations want to assign to their first line staff. This blog post will cover a way for first line to automate voice activation of users with the granularity necessary to cover several technologies such as Direct Routing and Operator Connect.
The main idea is to let first line operators use the tools they have access to when managing users without the demand of acquiring extra privileges.
By adding the Teams phone number in E.164 format to the users telephoneNumber field in AD/AAD and assigning the user as member of a defined security group, I have enough information to automate the Teams voice assignment for the user. This could also include license assignment through the group membership.