Is it possible to use a Dynamic Library of Slint to develope with Rust? e.g.: $ cargo run --features slint/dynamic_linking

This is not implemented at the moment. I believe bevy has such a method to speed up linking. I suppose something similar could be implemented for Slint, perhaps.

First Slint-App build downloads about 350 crates. How can I reduce the used dependencies? There are i-slint* crates that are not always used (e.g.: i-slint-backend-qt).

• What ist the min. config in cargeo.toml of dependencies for rendering with femtovg?

The minimum would be default-features = false, features = ["backend-winit", "renderer-femtovg", "compat-1-2"] on a desktop or embedded linux system.

• Can I exclude some crates in Rust-Analizer, to avoid indexing of all the modules?

I don't know if that's possible, but it sounds similar to rust-lang/rust-analyzer#8275