Do you have editors-pick topics in every individual category?
You could do this using CSS, yes. Something like
.featured-tiles-container {
gap: 1em;
}
This could also be done with CSS. To hide the 3rd, 4th and 5th square on mobile, you could do something like:
.mobile-view .featured-tiles-container > .featured-tile:nth-child(2) ~ .featured-tile {
display: none;
}