Looking for an Expert in B2B Ecommerce Website Developer

We currently have a Shopify Store that we want add more features such as adding dynamic bulk pricing and be able to order print on demand products while being more user-friendly. The task will include maintenance of the site such as modifying, adding or removing listings. All product listings will be on multiple marketplaces, such as Amazon US, Amazon UK, eBay, Shopify, Walmart, etc. All product listings will be managed from the ecomdash platform and pushed to the different marketplaces.