It isn't hard to start a new business. There are a ton off niches that Walmart and Amazon don't server well. Find one and serve it, then use profits to expand into the much larger (though lower margin!) areas that Walmart or Amazon serve. Good luck - it is not easy to run a business.
lol it’s not hard to start in tech with no regulation no capital or overhead. Real businesses are hard to start and live and die by the cost of financing
If Amazon or Walmart is part of your plan you need a better plan. Try selling oil well drilling supplies in oil country (I have family doing this, and they have cornered thus niche, so don't try that exactly, but it is the type of thing. They make it because they have in stock the special parts needes for that niche and Walmart won't)