The interesting thing about market tops is the perception of risk is framed by most as being less risky. When anything reaches the high point of its cycle, the upside potential is much less than the downside risk.
I recently re-read John Kenneth Galbraith’s book “A Short History of Financial Euphoria”. While it was published in 1993, it is as valid today as it was then. It is a quick read with at 110 pages of larger print.