I think what the author imply in this:
The same is true for investing. Research every stock you buy, every investment you make. Don’t follow the hype, don’t trust talking heads, don’t rely on hunches or instinct, don’t follow one or two simple rules/factors and ignore everything else about your investments. Remember that risk and reward are on a curve, and reach for the top of that curve. That’s the way to win the investment game.
Nothing new here, and as a rule of thumb, you don't need to over complicate things. I think this philosophy has been one of crypto tenet's: DYOR (Do Your Own Research). Which is very true, to minimized risk and to have a chance of greater reward, then obviously, you should do everything at your control and research first and not follow the hype around a project, simply as that.
And this what separates a good investors but an average one, you just pour their money on projects they haven't check out, but just throwing their money and then bitch around when they lost when the projects died, exit scam or just be used for pump-and-dump.
What I really meant was this particular line from the article I had link above:
As risk increases, reward increases, to a certain point. After that point is reached, as risk increases further, reward decreases.
Although there are times that higher risks yields a higher reward but not all the time because when that certain point is reached then the risks continues to rise but the reward decreases. We should be able to identify when we are at this so called "certain point" because it would be pointless to expose ourselves in greater risks but would not give you the expected greater reward.
On the other hand, we can consider the risk and the reward as independent to the other. The thought that I was trying to convey, the book rather, is that the amount of reward/profit isn't always determined by how much the risk there is which is very unlike to what most of the people had believed.