Igorltds
Godot is unlikely to ever implement official support for Rust, I don't even think they'd do many languages beyond C# in my opinion, to be honest. On top of that, the C# support for Godot is sub par...
The good news is that the C# support will get better for the same reason you can use Rust- it's going to be moved to GDExtension some time in the future, and Rust GDExtension bindings already exist and make the language quite a joy to use with Godot 🙂
The bindings are not perfect since Godot is far from 1:1 with Rust, but the people working on it have done an amazing job and put in tons of work. You can find the Discord here and the repo here.
As for ECS, Godot is not an ECS game engine. It makes use of high level composition, and you can implement aspects of the ECS pattern yourself, but fundamentally it is OOP. Here is an older article on it not being ECS, and one on some benefits of using Component-style design patterns.
Sorry you got so many snappy responses to this question. 😦