Keychron uses QMK and can be configured through their website or software and I believe it just flashes new firmware so you don't have to keep the software running.
Yeah, Rust is a special case because it handles almost everything at compile time. It also doesn't rely on garbage collecting like the majority of modern high level languages.
Derive macros are a godsend. There's macros to automatically implement serialization as well. Basically a Trait that can automatically be implemented when derived
It definitely doesn't. It's a horror game lol