For Shops in the EEA, UK, and Switzerland, Meta does not use algorithms to display product listings to users.
Location signal is used to filter products that are available in that region (if an advertiser has opted for localization of products by region). If an advertiser does not opt for localization, all of their products will be listed.
When showing products from an advertiser, products are sorted by price and recency of listing, with lowest priced items listed first, and, if there are multiple products of same price, then most recently listed items appear first.