How to make custom pages that can be filled with different content for a specific user of the site? For example, that this presentation https://news.mon.gov.ua is seen by a specific customer in the user menu, and not by all users.
See the Wix Code Tutorial: Building Your Own Members Area to get you started.
You can also use the wix-users API (with wix-users-backend) and Routers for full control over visitor/member access to pages and areas of you site.