Hello,
Composium – Visual Composer Extensions Addon plugin caused the problem on your site – https://prnt.sc/ymfii8 , when the plugin is disabled the Header builder works fine – https://prnt.sc/ymfb3w https://prnt.sc/ymfcd4
On the original website was Header builder used to create the header? If so, go to Theme Options > Header builder > Header templates > Export file, then go to site where the header is incorrect, Header templates > Import the header file (do not forget to disable the Composium plugin that causes js error).
Regards