Problem:
Elementor is not using the same language as backend language
Solution:
I can confirm (checked with the dev department) that this is the expected behavior and the way things work is: due to the fact that Elementor is a front-end editor, it uses the language of the front end, it does not matter what setting you choose in backend, the Elementor panel elements use the same language as the language of the page you are editing.
So what you are setting in backend for back-end language will not take effect in Elemetor FRONT END editor.
So this is not simply possible. 🙂