Oh; it's all client-only (GUI) right now. So I've only been using Dart in this app (stack), if I need to add server components (which eventually I likely will) I'll write those in Elixir and/or Rust (i.e. languages I already know).

Nothing against the idea of server-side Dart, I just don't see a reason to bother with it. I've never really been sold on the idea of using the "same language" for both frontend and backend. I (try to) prefer the right tool for the job; which for my requirements, this time, is mostly how I ended up with Dart and Flutter... and I've been pleasantly surprised. It is the first cross-platform desktop language & sdk pairing I've used that I, personally, don't totally hate. Every other time, I've just said "fuck this" and gone and implemented it whatever the native SDKs were.