Also, measure your eCommerce conversion level with shopper purchasing and checkout conduct in the Google Analytics dashboard. The JS redirect seems like a little bit of a messy problem, but to answer your dilemma: Should you set a canonical tag from ourdomain.be to ourdomain.be/en, then I would not advise like https://addons.prestashop.com/ru/seo-natural-search-engine-optimization/31857--rich-snippets-json-ld-opengraph-seo.html