Full-time stock trading or playing derivatives—what kind of profession is that?

Like a professional poker player.
Outsiders see it as one person, one computer, one phone, with free time—do whatever they want.
But actually? 90% of people lose money and drop out, the rest are constantly fighting their own greed and fear.
In the past, you could still compete with retail investors and take their money; now AI quant trading has entered the scene,
your opponent is an algorithm—emotionless, never gets carried away, executing in milliseconds.
Who are you fighting against?
The harshest part is, poker at least can be calculated with probabilities, but the stock market’s probabilities are constantly changing.
So that saying "zero threshold but actually the highest" is really not an exaggeration.
Anyone can open an account, but only those who survive inside are truly skilled.
If ordinary people really want to play, use spare money, don’t do it full-time, and keep a stable mindset.
Do you have anyone around you who trades full-time?
What happened to them in the end?