I wrote about building iOS and Android apps with haskell a while ago. Long story short, it’s non-trivial to do this right now, but it’s completely possible. simplex.chat, does have an iOS and Android application.
I’m in the process of revamping mobilehaskell.org to integrate the gist of the writeup, however there’s not much there yet. We do have a telegram channel for now.
Overall the best solution right now is to use haskell.nix, with ghc 8.10.7, (and all the patches that haskell.nix add on top) and have an aarch64 mac at hand.