I've been looking around and still didn't find any answers yet. My questions are:
How to output dynamic CSS inside media queries? In my mind, the CSS output from wordpress redux-framework has been written globally (both compiler/inline style) and will affect for all screen sizes.
What's the simpler way to output dynamic CSS in redux-framework in media queries way?
Haven't tested this, but should give you a rough start. You can use multiple fields (eg for 480, 768, 991 etc) and just output the code with wp_add_inline_style.
You would of course need to ensure proper escaping but this should get you what you need.