Why does Pendulum have less SHM at longer amplitudes compared to shorter amplitudes ?

Question

The effect of Simple Harmonic Motion of a Simple Pendulum decreases with increase in Amplitude relatively than that of less amplitude.

Answer 1

The longer the length of string, the farther the pendulum falls; and therefore, the longer the period, or back and forth swing of the pendulum. The greater the amplitude, or angle, the farther the pendulum falls; and therefore, the longer the period.

For a real pendulum, the vertical rise is only approximately proportional to the angular displacement from equilibrium.