Wordpress already uses srcset now. What I missed out was a simple way to handle and customize the sizes attribute—in my opion what makes srcset so effective. While I was at it, I also built in some extra functionality. Make it Srcset do not conflict with Wordpress built-in-solution.
SrcSet Responsive Images for Wordpress allows you to change the dimensions of images based on browser size by automatically adding the srcset attribute.
The must have media toolkit for WordPress. Edit individual image for specific screen sizes, organize media and images into folders, media tags, image credits, and much more.
Create truly responsive, art-directed images in the block editor. Wrap multiple Image blocks (Desktop/Tablet/Mobile/Custom) and render a single <picture> HTML element with correctly ordered <source media="…"> and editor previews that follow WordPress device switcher.