trend and change point plot

I originally built a linear growth model. However, the forecast looks like over forecasted. Then, I want to use Saturating growth. I set the growth='logistic' and tuned the cap value to try to make the future forecast lower. The trend plot is a logistic growth curve and gets much lower. However, the forecast doesn't follow logistic growth and doesn't get lower. The 'add_changepoints_to_plot' plotted the change point line (red line) which is not  logistic growth either. How to understand this?
How to make the forecast lower? Thanks