Old JS and New JS

I’ve gone into Webflow to build a new element for an old website that I built entirely in Webflow years ago and exported as HTML/JS/CSS to host elsewhere for a client.

The trouble is that the new JS that I have exported and use cancels out some of the functions in the old JS and vice versa and at 22k lines of code in the new JS file there’s no chance of me working out what is what.

Do I need to rebuild the entire website again?

Here is my public share link: LINK
(how to access public share link)