Plenty for iOS to chose from, Christian’s legacy continues. Memmy and Mlem both feel pretty close to Apollo - and are both directly inspired by it.
These apps are in early beta. They have constant updates (daily for Memmy and weekly for Mlem), so you can kind of see them being built in real time. If you’re patient with the developers, you’ll get that Apollo experience very soon. It’s like 80% of the way there.
Liftoff is pretty cool too, though it’s a different design approach.