People have been trying for, IIRC, 15+ years to add a full-fledged type system to Erlang, and the distributed nature keeps defeating them. This problem may never be solved.
Not sure what compromises were made, but it was a sore point for users of the library for years to throw around untyped messages when the host language (Scala) provided such a powerful type system.
We do however have typed message passing libraries in Gleam that are in part inspired by Akka Typed.