Dear,
I installed the new Material template on my site where the clean mart template was present.

Current version of
Joomla! 3.9.21
VirtueMart 3.8.4 10335

The problems are:
- the backend configuration is not working correctly: clicking on any of the tabs present does not open the corresponding tab
(Category - General Category - ListView Category - GridView Category - MultiGridView Product Details - Zoom Effect - VM Product Module)
- the front-end does not correctly display the product Details and categories pages like the demo.

The website is under development and the path is hidden by the dns so if you need to check it I have to send you an e-mail with the specifications

Please, let me know as i can check or do.
Thank you

Roberto

For additional test, I have buyed and installing the last version if T3 template (template that you have suggest on your DEMO site).
The problem is always same.