And Amazon is using this monopoly leverage to squeeze its small shippers. Amazon makes them pay to advertise on Amazon, but Amazon's own products get top billing for free. Amazon makes them pay for shipping, but Amazon ships its own products for cheap. Amazon punishes them if they list their products anywhere else for a lower price. And when Amazon sees a seller who has found a successful niche, Amazon can put its own product at the top of the search page for cheaper and instantly shove them out of that niche. "Both a marketplace and a competitor."
Holding on to a few shares (as a regular joe), you do not have any influence on the company (re: enshittification). A monopoly that is publicly owned, does not make the situation more palatable.
The land for your business is at least in a country that isn't ran by you if not also just owned by a landlord that isn't you.
The materials you use to run your business are almost certain sourced from not you.
The lesson isn't "Don't build your castle in other people's kingdoms" it's make sure you have contingencies for your suppliers.