Does wearing sunglasses on top of the hijab, on the head, in the shade or indoors, constitute adornment, knowing that it facilitates their re-use? And is wearing necklaces over modest clothing or rings forbidden?

It is not permissible for a woman to wear glasses in a way that draws the attention of non-mahram men, because it is an adornment that is forbidden to display. Every action that incites فتنة (temptation/strife) is measured similarly. However, if it does not draw attention, then there is no harm. It is not permissible to wear necklaces or display rings in front of non-mahram men, because both are considered adornments.