No, capitalism is not a belief system. That’s just marxists’ image of capitalism

False. Not that it matters since you're wrong, but I'm no Marxist. Not a fan of authoritarianism.

Capitalism is when a free market results in some people deciding to get wage jobs instead of being entrepreneurs

Nope. People being employed by other people is MUCH older than capitalism and present in most economic systems.

When you get a worker class, who accepts the trade of more income security for less potential profit, ie when there are “jobs” in the private sector, then you’ve got capitalism.

Wrong again. Do you eb know what the word "capital" means? 🙄

Because capitalism is based on free markets, ie markets where people have choice of how they engage, a successful capitalist is one who resists short term greed in favor of long term profits.

You almost couldn't be more wrong.

Under-regulated capitalism, which is the purest form and the kind dominant in for example the US, inevitably leads to the already powerful consolidating and abusing their power, taking away the choices of workers.

It also leads to exactly what you say it doesn't: chasing short term gains at the expense of everything else, including the long term survival of humanity.