Hmmm… i haven’t tested it with Elementor, i am not sure why it wouldn’t work ( apart from background images ) as it just adds a srcset attribute for the image. Have you spoken with Elementor about this?
And they offered no other advice on how to use Retina images with their product?
Problem we have is Elementor prints the HTML so if they are leaving behind the necessary attributes we cant really assist with fixing that.
I am afraid there is not much we can do, it would require some serious custom development to add the necessary sources to Elementors markup. Maybe this is why they haven’t done it or they don’t feel there is a need for it. I checked their Github and it was only raised once as an issue. So not much demand has been generated.