Shopify Schema Markup for Reviews Widget might be pretty difficult (as it depends on the review apps that you're using), I like to recommend you leave it for the industry experts.  There is a unique target in mind for your Business — a lot more visibility, traffic, conversion, and revenue. https://www.presta-addons-modules.com/en/front-office/prestashop-geoip-popup-message-and-redirect-links-based-on-country.html