Please check the site in the front-end not in the editing mode. Also, check the site on the real devices. If you want to narrow the browser, reload the page and check.
All the structure is responsive. As for the background images, it is not our theme reason, it is the nature of the image on the background it is cut. You can check your images on any default theme and you will see the same. There are two ways of solving such an issue: 1. to replace the image with the color or create a clone column with the smaller image on the background and hide the desktop column and show the mobile column https://wpbakery.com/video-academy/control-elements-different-devices-responsive-column-controls/
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