If you are using consistent semantic global classes on every page, as you are an experienced developer there is a straightforward solution using custom css or a custom stylesheet.
For example, if your hero blocks all have a class of .hero, you can hide the background image using a media query for the mobile breakpoint and target the .hero class with background: none (or whatever other background you need).
There was some mention recently about work being done on this, so it is possible an upcoming release will include it, for now though, some custom CSS is a quick workaround.
You can also vote on this feature request if you want: