In the Teams admin center (https://admin.teams.microsoft.com/devices/manage), under Manage Devices you have All Devices and Configuration Profiles. There is no way to dynamically apply Configuration Profiles at this time, so you have to wait for devices to register (whenever the user decides to finally log into their new device) before you can apply a profile to the device. Until this happens, the phone defaults its time zone to the manufacturer setting. In the case of Yealink, its China. It is hard to detect new devices sans profiles. I'd like to request that the Configuration Profile name be added as a column to the All Devices list. This way, at minimum I can select the ones missing a profile and then send the correct one to them. There is so much missing here, but this one simple change could make it so we can get by while we await a more fully featured solution.