There are some things you run into with Teams and Microsoft 365 in general that require fixing via PowerShell.  Here's how to get started, and some of the things I've encountered that needed PS to resolve.

Install, Import, and Connect

Install-Module -Name MicrosoftTeams
Import-Module -Name MicrosoftTeams
Connect-MicrosoftTeams

Now Do Stuff

Problem: User-A  lives in New York.  They have their M365 profile and local laptop all set to use Eastern Standard Time.   When a User-B in Mountain Standard Time hovers over User-A's contact information in Teams, User-A is reported to be one hour behind User-B.  This suggests Teams is set to Pacific Standard Time.   User-A is unable to find any reference to Pacific time in their settings.

 Diagnostic: Run the following PowerShell commands to collect information on User-A's M365 settings.

Get-MailboxRegionalConfiguration -Identity "user@email.com"| FL
Get-MailboxCalendarConfiguration -Identity "user@email.com" | FL

In this instance, WorkingHoursTimeZone was reporting Pacific Standard Time in the MailboxCalendarConfiguration output.

Resolution: Run the following PowerShell to fix this.

Set-MailboxCalendarConfiguration -Identity "user@email.com" -WorkingHoursTimeZone "Eastern Standard Time"

 Verification: It can take up to 24 hours for everything cloud-related to sync up, but the user's contact info should reflect the current time zone after this delay.   In my experience it usually only takes a few hours to show. 

Now that you're connected to Teams you can do all kinds of fun stuff.   Enjoy!