Hello, biotxacur!
1.Go to: WooCommerce > Products.
2.Select the Add Product button or Edit an existing product. The Product Data displays.
3.Select Variable product from the Product Data dropdown.
https://prnt.sc/pe69k7
Please check the following article:
https://docs.woocommerce.com/document/variable-product/
Besides the plugin you mentioned, you have 33 more active plugins.
Having too many active plugins is not a good idea since it can increase the possibility of some conflict
and slow down your website.
Regards