I have just got off the phone with support and they have told me at this time there is no option for changing the time zone for the analytics and reports inside the admin center for teams. This makes it a bit confusing when trying to track down a certain call. Hopefully this option can be added soon.
Side note: Not to be confused for changing the time zone on your personal account settings, which seems to have no affect on the time zone listed for reports.
That's expected, none of the reports in M365 allow you do to that and use UTC as standard. The difference with Teams report is that the latter are only available within the portal and cannot be accessed via API, where you can usually make on-the-fly changes in the datetime format. That said, most of the data isn't as granular anyway, and only includes the date field.