I can confirm this unqiue id problem exists for all elements inside of a singular repeater, text, image, whatever, it will have this problem and thus cannot be manipulated with Code or even integrated with Code to do anything from what I can see.
I read this entire thing and still feel just as confused as to how am i supposed to handle this need.
https://www.wix.com/code/reference/$w.Repeater.html 
I cannot help but feel as though this is a limitation by design (or an underthought/oversight?) that is going to impose needless complication to the level of coding required just to get a unique id to an element in a repeater adn get it to trigger unique actions. #feelsbadman