Responsive 3 column preview card component using flexbox

Would like to know if the layout is fine or few more tweaks are needed.

I got an html validation error stating that section should have a heading else we should use a div tag instead. So I added sr-only to add an h2 heading for screen readers only since there was no visual heading. Would like to know if this approach is correct or I should have simply switched to a div instead.

Any feedback is greatly appreciated.