Hi,
I’ve just bought Improved Variable Product Attributes for Woocommerce. According to plugin’s author it should work with Legenda, but it doesn’t.
This plugin displays simple product attributes as variations in variable products. See https://tshirt-gallery.pl/produkt/zestaw-koszulek-dla-par-piekna-bestia-01/ You can choose size and color of t-shirts. This plugin doesn’t allow to add product to the cart until all required attributes are selected. It works well with Storefront. If some options aren’t selected you can’t clik add to cart button (but you see it). With Legenda the checking process is ignored and you can add product to the cart without selecting any options. Moreover, on shop page there are add to cart button instead of “select options” buttons and of course you can buy products with no options.