Name Change Not Updating in Teams
There are multiple syncs that need to happen on the backend, and there's nothing you can do until they complete. Then, there is the client cache factor, which might add additional delays. If Computer Services confirms the new name is displayed properly in the Teams admin center, you can assume the backend sync is done, so you can try clearing Teams cache,
To clear your Teams desktop app cache:
Sign out on Teams
Cancel teams if it tries to start up again or quit Microsoft Teams by right clicking the icon and select Quit
On your keyboard, hold Windows key and Press R
Copy and paste %appdata%\Microsoft\Teams into the RUN window and then press OK
Delete the contents of this entire \Microsoft\Teams folder. If you get an error on something, just skip
Restart Microsoft Teams
Sign In if prompted
The new name should be displayed
(Please note that deleting this folder does not delete past history, saved groups or files. All that info is stored on the Team server and will be re-downloaded the first time you start Teams)