Presale plugin

Free variant you can find here can edit price and stock level for products and variations. Full version can edit everything even a filed used by other plugins.

perfect and in the pro version, can you update variants by .csv?

Yes you can import/export CSV, if you take package with muti-import add-on there is option to also use XLSX and ODT.

great and where should I buy the plugin by themeforest?

This is the durect link:

https://holest.com/holest-outsourcing/joomla-wordpress/excel-like-manager-for-woocommerce-and-wp-e-commerce.html

thanks!!!