Trading courses and coaches are useless- true or not

How to understand the phrase "the simpler the trading system, the better"?

What is the degree of simplicity here? Or the simplicity here is not what I thought, just use a few indicators, so what do you think of this sentence?

For the real-time market, should we keep our original intention or follow the trend?

What should I do if I am about to liquidate?

Tell me how hard you have worked to make money in trading?

In the past few months, I feel that the more I study, the more I study, but it will decline. Sometimes I feel conflicted. I don’t know why?