I have been trying in the past few days to solve this problem and i can’t

Whenever I add an addEventListener, or a toggle in javascript, I get ”can’t read **** of null” or ”can’t read of undefined”. I tried many different ways to solve it, deleting the javascript file and recreating it, putting everything inside an “addEventListener(‘DOMContentLoaded, …’), moving the javascript code in html file. Nothing works, I don’t know why. I tried all the ways that they say on the internet that work.

enter image description here