There’s no way of doing this afaik! If you are an owner you will be able to delete the group! It is possible to restore an deleted group for 30 days though! Also by using retention policies etc you can make sure msg and files are kept!
There is a uservoice for this one which is known by Microsoft
@Taen keren you can configure retention for Teams conversations and for the files through SharePoint, it doesn't retain the Team itself but content will be available in content search. You could write powershell to apply retention based on classification.