@Yaro I have imported products that created over 200 variation without a hiccup on woocommerce? For example, an iPhone case that fits iPhones 5, 5s, 6, 6s, 7, 7s, 8, 8s, 9, 9s, X, Xs, Xs Max, XR and also has 15 colors ( 15 colors * 15 phone models = 225 variations add).
Well I shouldn't say "without" a hiccup. I had to set the status 'allow theme to handle attributes' in the 'Nice Attributes' section because something was unable to handle it. Also its a complete nightmare not to be able to 'Split by variation' like you can in the original plugin and have to go through and duplicate, then delete every variation + attribute you don't want (a lot of cell phone cases are completely unrelated to each other, ex: sellers will mix mickey mouse with floral).
And for some reason the plugin like ignores the .CSV importer for woocommerce. I've exported all variations gone through an entire .CSV full of of every product and its variation marking each of the ones I don't want from 'published' to 'trash' and for some reason they are not only still there, but still enabled. Also I have tried deleting all variations (inside woo block on product page) and then recreating the variations with the modified attributes (just the colors or phone models I want) and then the product won't update (even though the seller, URL, and everything is still there).
I have also already submitted a suggestion to woocommerce to give up check boxes for deleting variations instead of singly or all of them (being the only 2 choices atm). But who knows if that will ever get considered. So I also submit a suggestion to allow us to re-import same product from alidropship plugin without deleting the previous post (so we remove and modify variations before getting to woo), have not gotten a response back from that either. Might not even be possible but hey, gotta try because it can take over an hour to delete 200 variations to keep the 5-15 you actually want for that duplicate post.