I am looking for a solution with Multistore or something like that. The task is to have more than 5 sites with the same path to the template, but with different products / product prices, addresses and admin panel for orders
What can be done to accomplish this task?
In config.php
define('DIR_TEMPLATE', DIR_APPLICATION . 'view/theme/');
Controls where the templates are and you should be able to load the templates from a single directory outside the document root.
You could also make "view/theme" a symbolic link to a common shared directory outside of the webroot.
This may become a nightmare to manage over the long term unless you keep all the separate systems identical and never install any modules.