Again, it is seriously something with WordPress.
Again, This is seriously nothing to do with WordPress.
From everything you’ve written here; you seem to want to host WordPress on one domain and server, but have a domain hosted on another server someplace else point back to the server and domain which contains your WordPress installation.
This is what we call a redirect.
You accomplish this by modifying the .htaccess file of the domain you wish to point someplace else.
Again, if you read the material in the link I left you, you will find the following:
htaccess uses redirect to look for any request for a specific page (or a non-specific location, though this can cause infinite loops) and if it finds that request, it forwards it to a new page you have specified
Meaning that if I enter the url https://somedomain.com but you want it to point to https://wordpress_here.com, that is a redirect.
Again, from the link I left you:
Note that there are 3 parts to that, which should all be on one line : the Redirect command, the location of the file/directory you want redirected relative to the root of your site (/olddirectory/oldfile.html = yoursite.com/olddirectory/oldfile.html) and the full URL of the location you want that request sent to. Each of the 3 is separated by a single space, but all on one line. You can also redirect an entire directory by simple using Redirect /olddirectory https://yoursite.com/newdirectory/
Using this method, you can redirect any number of pages no matter what you do to your directory structure. It is the fastest method that is a global affect.
You need to have access to the .htaccess file of the domain you want to redirect, and you need to modify that .htaccess file in the manner described above.
For the life of me I cannot understand why you keep installing and uninstalling WordPress and are expecting something different to happen, especially when you’ve been offered a pretty standard (and correct) answer to solve your problem, and more importantly when this has nothing to do with WordPress.
And for the last time, this has nothing to do with WordPress.