This feature request is now on the backlog.
I’ll keep you posted as we move through development!
More over, when you drag a folder structure, all files get copied flat into the current channel folder. To get this working properly, you have to used Sharepoint and drop the folder structure there. Teams is useless for such file imports. You'll loose any structure.
This feature request is still in the works. No additional updates are available at this time. I’ll keep you posted as I hear more.
When using Teams in Firefox I can choose whether to open a file in the online version of Word/Excep/PowerPoint or in the installed ones. But the desktop application for macOS does only offer to open in the online Office applications. Please add the ability to open Teams files directly in the installed Office applications to the desktop version of Teams as well.