Yup, I have the beta versions of voyager, memmy, and mlem on my phone and just alternately switch to whichever app gets a new update; or if one happens to be buggy or unstable.
Push notification actually cost money to run, so unless the dev has some money to burn (either out of their own pocket or donations) it probably won't happen. Even Sync will only offer push notification for ultra subscribers.
Voyager is the only option as far as I know. And unfortunately, it seems Apollo dev Christian Selig is not interested in converting Apollo to use Lemmy’s api at this time since he seems to ignore comments that suggest it.