Your last sentence is basically where I'm at, writing my backends in Rust these days. I'm interested in the BEAM promise of letting things crash but not sure how good that is in Gleam due to its OTP still being somewhat immature as the devs are rewriting GenServer as a typed library.
Hello! I'm the maintainer of Gleam. We are not rewriting OTP, regular OTP is used in Gleam. Most commonly the typed Gleam APIs for OTP are used, but you can use the untyped Erlang APIs if you wish.
This is the same as in Elixir, where macro-enabled APIs are offered, and they just wrap the regular Erlang APIs.