You are trying to find the functionality to copy a section of the screen, however you are not finding it in the Adapt Mode on Fiori as you are used to do in HTML UI.
SAP Cloud for Customer
The copy of a section is not available for Fiori Adaptation Mode.
This functionality was replaced by the option to Move the UI element from one UI to another one.
Fiori adapt mode, adaptation, UI copy section , KBA , AP-RC-UIF-FLX-FRW , UI Adaptation Framework , Product Enhancement