I Have used the woocommerce variation gallery plugin for adding woocommerce variation extra images. I did all the steps you mentioned in the tutorial to make that plugin works with our X-store theme after that too it’s not working clearly.
Here’s the product link you can check
https://dev.primedeco.de/product/spritzschutz-herdabdeckplatte-schneidebrett-aus-glas-grune-wiese-auf-holz-senkrecht/
You can see the gallery is not working well but if you choose the variation multiple times it works fine so please check it.
Also if there is an option to import images to the theme default variation gallery images. I am using WP ALL IMPORT Currently.