Microsoft is changing the way new teams are created in the Teams admin center to make sure that their settings are consistent with teams created in other interfaces. It’s a good idea because it means that all teams are then created equal. Organizations who wish to use different settings can update teams once they’re created using either PowerShell or the Graph API.
Teams has released version 0.9.6 of its PowerShell module. You should upgrade to the new module because it fixes some bugs and allows administrators to manage any team, even when they’re not a team owner.
A quirky side of the New-Team cmdlet is that it creates some interesting values for the properties of the underlying Office 365 group that you might like to control better. As it turns out, the Alias parameter is what you need to set.