News of the eCommerce boom has only increased in intensity as we start to slowly escape from COVID.

How do you square that with the fact that I struggle every day to grow? Why do others have it easier?

First, your expectations are probably wrong. You aren't going to get rich quick. It's an operator's game. If you count the pennies at the beginning, you will be able to count the dollars later. It starts with your financial model.

Second, you still have not defined why you are different. You sell a widget because you found a supplier, fantastic. How long did that take you? What's unique about that? There are hundreds of thousands of suppliers just begging you to start that next eCommerce business. Why should your consumer care? Don't confuse "a consumer can shop for X on my site" with "a consumer will feel compelled to buy X on my site because of ...., rather than ... ". Likely you have the former, not the latter. If your answer to the second point has absolutely anything to do with how great you are at advertising, you are missing the point.

Third, your site is probably slow. If your site isn't fast, people aren't going to want to stay on it. That's it.

If you don't start here, it doesn't matter what you put on your site, how you promote it on Facebook, etc.