In the old editor, while editing a table, the users were able to copy/cut/paste rows and columns by clicking on the buttons available.
In the new editor, there are no buttons for these actions and the only way to copy/cut/paste the rows and columns is by using keyboard shortcuts.
Please see the attachments for reference: the screenshot for the new editor and the recording for the old editor.
Add the same buttons/functionality to the new editor.
Use the cmd/ctrl+c/x/v commands from keyboard.