Nowadays you have to make everything as easy as possible for the customer. With a product you can set yourself apart from the competition and share your advertising budget better on Facebook, Google and Co. Try to give your customers a unique experience. In addition, with a one product store you have the advantage that, for example, your Facebook advertising pixel receives better and more precise data and you can save a lot of advertising budget and scale it better.
For example, if you now promote product A and send people with a promotional video of product A on product page A, then you still have the problem that when someone orders product B or C in your store, your Facebook pixel collects useless data for the promotion of Product A. Then the Facebook Pixel will send you people who are more likely to buy Product B or C, thats why the most general and niche stores are not profitable and their stores die out quickly.
If you have a one product store, you can switch to your main product anywhere and it's all about that product. This gives your customers a better buying experience and you stand out from your competition in the dropshipping business. You can also start branding your product to make yourself unique for long-term success.