There are a lot of users asking to be able to create a team from a Template.

From UserVoice it says that creating Teams from Template is on the backlog :

Last week at the SharePoint Conference North America,  at the Microsoft Teams booth I saw that we could Create Team from Template. (See image below)

It would then show the list of available teams to use as a Template.

Don’t hold your breath, It’s still in testing, but it looks good.

Maybe you will see this soon in a tenant near you!