You cannot copy the whole structure of Team. You can copy the following parts in Team using POST /teams/{id}/clone Graph API
apps - Copies Microsoft Teams apps that are installed in the team.
channels – Copies the channel structure (but not the messages in the channel).
members – Copies the members and owners of the group.
settings – Copies all settings within the team, along with key group settings.
tabs – Copies the tabs within channels.
When tabs are cloned, they are put into an unconfigured state -- they are displayed on the tab bar in Microsoft Teams, and the first time you open them, you'll go through the configuration screen. (If the person opening the tab does not have permission to configure apps, they will see a message explaining that the tab hasn't been configured.)
When we tried with same app install in clone team it gives message App already exist. Could you please check it once or share screenshots or repro steps so we can try it from our end?
Ref. Doc:-https://learn.microsoft.com/en-us/graph/api/team-clone?view=graph-rest-1.0&tabs=http