By adding those constants to wp-config.php you're overruling any setting in the database. That's why you can't edit them in the admin panel.
So the first step is to change those constants to:
define('WP_HOME','https://domain.com');
define('WP_SITEURL','https://domain.com');
Then delete your htaccess file. (.htaccess in your root folder).
Once you've done this navigate to http://domain.com/wp-login.php
Login to your site and go to Settings -> Permalinks. Hit save which will regenerate your htaccess file.
Finally you'll need to update existing links. I'd suggest installing a plugin called 'Velvet Blues Update URLs'.