New php page – Essentially mirror of index page

I am a web designer and have created a wordpress blog for one of my clients: https://www.westlarealestategroup.com/blog/

He would like to create a mirror of this site, with the same posts and content, but with a different header (different logo and navigation options). It should be something like https://www.westlarealestategroup.com/blog/index2.php, which I can then have another domain name forward to.

Is it possible to create such a page? If so, how? I tried to create an “index2.php” page in the theme folder, but it’s obviously not forwarding correctly.

I know html and css very well, but I’m still learning php, so format responses appropriately ??

Thanks for your help!