The self-confidence factor must also be balanced with good knowledge about trading. Don't rely on yourself when you don't know what to do. it will only give you a loss because you are only making guesses without any analysis. Profits and losses are natural, but if you experience losses because you don't understand anything, that's stupidity and if you keep winning, it's just luck.
I rarely see traders keep winning, implying that they are continuously winning money, its more like they are profiting and losing but the newt amount is positive. Luck is not the full reason here, skills do apply as long as we keep ourselves limited to "spot" trading which is the trading method. Anything other than spot trading is a gambling and entering those increases your risk just like EV- gambling.
Eventually a trader understand how the spot market works and how to take advantage of market movements.