At the moment we only offer the option to edit prices via Gelato API Dashboard for specific products.
It can be done for a specific product and related variants on the product page using buttons Edit product → Edit prices
If you would like to update prices for all your Shopify products, it's recommended doing it via your Shopify admin account. In section 'Products' you can check mark all products and then click on 'Edit products'. You will see the chart with the product titles, variants and prices. This way you can update prices for all products and variants directly on Shopify.
You could refer to Shopify Help center article: https://help.shopify.com/en/manual/shopify-admin/productivity-tools/bulk-editing#step-2-select-product-properties-to-edit
Also see screenshots below as a reference
