When is the right time to sell?

Yes, it’s called apophenia.

I get you have a strong opinion, and I completely agree that a stock chart is useless at predicting anything at all - it can only give a picture of what is happening right now. I.e. If a chart can alert me that the Nasdaq is suddenly crashing, that is useful information which I can use to buy, sell or rebalance. People also use charts to figure out where to set limit orders to buy and sell.

If charts were completely useless, then why does Freetrade bother to display a chart at all?