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 to do it via your Shopify admin account. In the section 'Products' you can check mark all products and then click on 'Bulk edit'. 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 can refer to the Shopify Help Center article here.
Also, see the screenshots below as a reference: