Not able to get the control of buttons in TdxRibbon using the TestComplete in Delphi

Ribbons and tool bars like this are such that the buttons are not individual objects themselves but are items on the tool bar.  To interact with the buttons, you would use the method on the TdxRibbon of "ClickItem" which takes a parameter of either a string correponding to the item or the item index.

See https://support.smartbear.com/testcomplete/docs/reference/test-objects/controls/desktop/dev-express/vcl/ribbon/index.html