I would like to start a new e-commerce platform build with Shopify/Hydrogen (React) an I'm still not sure about the back-end side (maybe ExpressJS + DynamoDB). The issue is that I want to host everything on AWS, I am new there and I don't really know in which direction should I go. Basically the platform is created for selling fishing stuff but it should also support the drop-shipping context, where other companies can sell their own products there. Can anyone help me with a path for achieving this? What are the right steps?
Regarding headless storefronts you have multiple options with hosting, starting from Gatsby Cloud, through Netlify, Vercel or Amazon Amplify in case you want to host it on AWS.
I will assume that "drop-shipping context" would mean you want to become a some sort of a marketplace? Where other merchants would list their products and upon purchase handle the shipping themselves? You can organize that through using free open-source CMS - Strapi in a manner where it acts as a PIM (product information management system), basically you will create users in admin panel and allow them to put products into CMS and then pull and publish them to Shopify storefront (through Admin API you can even create products and add them to an order on the fly), also through webhooks that Shopify trigger on the purchase event you will be able to send a notification to a dropshipper.
Regarding Hydrogen it's pretty early in the making so I would suggest to take a look on React-powered boilerplates out on Github and it will boost implementation speed significantly.