pages and login not working

my site has no title so I decided to give the site a title as elpeeps from the general settings and that caused the whole problem after. the only page that shows now is the registeration and login page but when i enter any login it ramains the same.
my site address is https://www.advghana.com/wp that is the site url but when i try to go any other page it result to
Not Found
The requested URL /elpeeps/index.php was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

The solution below which was recommended for the problem above did not work.

Edit functions.php
If you have access to the site via FTP, then this method will help you quickly get a site back up and running, if you changed those values incorrectly.

1. FTP to the site, and get a copy of the active theme’s functions.php file. You’re going to edit it in a simple text editor (like notepad) and upload it back to the site.

2. Add these two lines to the file, immediately after the initial “<?php” line.

update_option(‘siteurl’,’https://example.com/blog&#8217;);
update_option(‘home’,’https://example.com/blog&#8217;);
Use your own URL instead of example.com, obviously.

3. Upload the file back to your site, in the same location. FileZilla offers a handy “edit file” function to do all of the above rapidly; if you can use that, do so.

4. Load the login or admin page a couple of times. The site should come back up.

5. Repeat the above steps, but remove those lines. IMPORTANT: Do NOT leave those lines in there. Remove them immediately after the site is up and running again.

If there is no functions.php file in the theme:

Create a new text file called “functions.php”.

Edit it with notepad, and add this text to it, using your own URL instead of example.com:

Please i need your help. Thanks