There are none on the App Store yet. All of them are still in Beta. You don’t need to “hack” anything, you just need to install TestFlight which is Apples app beta testing program. Then sign up to be a tester for the apps.
Memmy is the app that currently gives me the most Apollo-like user experience. There are still elements that need to be refined but overall it is the best app for a painless migration from Reddit.