So figma does not seem to have a full “flex based min-max fr” logic set up for a designer to take advantage of yet. What I mean by that is setting reflow logic on containers like cards and grid systems. Think more of a dev tool like in webflow for these types of feature to make this easier to quickly set the logic.
500px - 31.25 rem min/ 584px-1fr MAX
300px - 18.75 rem min/ 378.67px-1fr MAX
Till then though I have been able to fake a min-height at least creating a frame as a null within a responsive container. In this case min is 560 height so if user does not use much content it at least holds at that height.
I did not find any solution out there yet in the community other than faking min width. so wanted to share and push towards an better min-max figma world. If anyone has any creative solutions or feel the same let me know. I can share more of my rigs for reflow tricks as well.