Would it be possible to update the iOS app badge with a count of unread notifications. I might be wrong, but I don’t think the badge shows anything at the moment.
Thank you for the request and welcome to the forum!
We have consider that and the biggest issue is consistency and what “unread notifications” means.
Most communities are active so the app would constantly be badged for most folks, does knowing you have 4 vs 25 unread make a difference, possibly but likely not. For less active communities, push notifications suffices.
So the low value-add along with the technical challenges that I won’t get in to currently makes this a not so important feature.
But feel free to make a case for it to change my mind. 
I would set the app badge to be the number of outstanding notifications for the user.