Handling multiple calls at the same time in Teams Phone is a very painful experience. Users often end up losing one of the calls. This there anything in the roadmap about addressing this? This is actually the main reason we are not deploying Teams Phone across our company.
I would need more information on the multiple calls scenario. If you are treating the calls as a regular inbound calls yes it is very difficult for the users. My recommendation would be to use Microsoft Teams Call Queue and Auto Attendant function in conjunction with Presence based routing. This would ensure that the end customers who are calling into the Auto Attendant and Call Queue hear the hold music till the calls are answered by the users.
The use case varies from department to department. In addition the Auto Attendant and Call Queue can be a solution for your regular Microsoft Teams Telephony users as well. It is not always meant for Contact Center Solution.
Let me know in case you need any additional information.