All advanced server management tools are located in the More section of your control panel.
You can find this section at the bottom-left menu. From there, you can access tools such as:
Server Importer
Player & Subdomain Manager
Version & Modpack Selector
Mod & Plugin Installer
World & Config Changer
And more..
These tools allow you to fully customize and manage your server without manual file editing.
If the issue persists, please submit a ticket.