Are there any Python scripts for making turtles move in cubic Bezier curves?
A bezier curve program should return a list of points or line segments. It is up to the user of such program to actually draw the segments. Searching python turtle cubic bezier, which you should have done, returns two examples of doing so (or of directly incorporating bezier code).
https://github.com/yuxuan0712/draw-a-heart-using-python-turtle
https://www.coursehero.com/file/229558868/BezierCurvepy/