I actually wish we had it for everything! Just set it to repeat all notifications after 5 minutes unless the screen has been activated to show them.And can someone please explain why we still don't have this option on Calendar events?
I have missed way too many appointments because Apple refuses to give us repeat alerts.
However, as I doubt that'll ever happen, you can simply create two event alarms. Of course, that means the second one will still trigger even if you cleared the first one, but it's better than nothing.