You confuse the two type of texts.
There is independent texts (the text you can add with the tool bar)
And the element texts (owned by element)
The picture of the QET global config, "Dynamic texts" is for configur the element texts (it's true the title is not explicit, I will change it to avoid any confusion).
The picture of your post 8 "Auswahl.bmp" is for edit the independent text.
The picture of Nuri at post 2 is for edit the element texts.
That why you configure a text, but 'don't work', you configure element texts, but you use independent texts.
For the moment there only the element texts that can have a default configuration.
Right now I'm working on element texts, to let user define for each element texts the font, trough the widget at post 2.
After that I will add a global configuration for the independent text (like what already exist for the element texts)
I hope I was helping you to better understand how work texts in QET.