srcset script: Retina ready (2x size) and various sizes of the same image

I have am using Elementor page builder on Astra Theme. I cannot figure out if the images for retina display (and different sizes of the same image) are handled automatically, or do we need to add src script ourselves to render the correct size image to the browsers?

Does the Elementor (or Astra) come ready with srcset script to render/serve the right size images for Retina display?

As per the WordPress, “Responsive images are automatically supported by WordPress core. Image markup will automatically include srcset and sizes attributes for images uploaded to a WordPress site’s Media Library.” I don’t know, if that itself has taken care of the issue of rendering the right images.

Question is, should we remain confident that as long we have uploaded two sizes of the image in this manner—[email protected] and [email protected], retina image (2x) will be served / rendered by the browsers?

OR, do we need to add our own srcset script to achieve the proper rendition of images. If yes, how it can be accomplished.

On the same line, the second question is: can we apply the “vw” attribute to containers? vw attribute becomes useful in modifying the style for mobile devices.

The page I need help with: [log in to see the link]