It just has many features that can be overridden with Python code so they can have any behaviour at runtime. For example when you access an object attribute it can literally do anything: https://docs.python.org/3/reference/datamodel.html#customizi...
You could probably optimistically optimise some code, assuming it doesn't use any of the dynamic features of Python. You're going to get crazy performance cliffs though.
I have seen this mentioned multiple times, someone as a good reference explaining what makes python more dynamic than JS ?