Now, just because the “digital” realm is large doesn’t mean it’s devoid of the way in which “markets” typically work. Competition is obviously a major force, as is the idea that because something is “easy”, it can be replicated relatively simply by others (leading to an erosion of your profits).
Selling on Amazon typically works by providing access to products which people either don’t have access to locally, or are able to obtain locally but with major restrictions (such as color/size issues), or with problems in reliability of supply. In other words, whilst the Amazon marketplace is vast – don’t think you can outwit supply/demand. https://www.freightvp.com/
The real trick with “digital” businesses is to provide access to unique products (typically made by yourself or your company) which are only available through you. These products have to be focused on providing a solution that most people have no idea about, and thus makes the proposition of buying it through the Internet legitimate.
Obviously, creating a “unique” product is 1,000x easier said-than-done – the trick with it is to work on solutions to your own problems. Work towards sharpening a skillset, which you’re able to apply to a wider audience, from which you’ll be able to identify “products” which can be created and offered as a means to simplify/solve problems you’ve experienced yourself.