Is the js code written correctly and can it be optimized / written better somehow?

Question

JavaScript

Good day!
While freelancing, I somehow stumbled upon an order where the layout was divided into sections and when the mouse was scrolling, the site smoothly scrolled to the next / previous section.
At that time, I didn’t know js at all, so I didn’t know how to make such functionality.
Now I learned something and wrote the following code in a whole day:
https://codepen.io/Kononov_D/pen/GeqbaX
And ​​I would like people who understand better than me to advise what could be done better / point out mistakes (yes, the functions are called crookedly, obliquely, but this is not a mistake)
I also do not quite understand how you can make a controlled scroll to an element, because here is a design

window.scrollTo({
    top: offsetTop,
    behavior: "smooth"
  });

scrolls for some, indefinite time. What if I want the scroll to last 1 second and have an ease effect?
Thank you.