This is a bad idea. You can make Linux look like Windows on the surface but people are going to then be surprised and frustrated when it doesn't act like Windows, it will come off as cheap imitation. People get confused about the idea of something as simple as the concept of a single root file system, they will not understand that coming from a world of C, D, and E drives. It's best to make it look foreign to them so that they don't have their expectations subverted when they realize it actually is a fundamentally different operating system.
I wish it would get LSP support. There are some plugins but they seem buggy/ incomplete/ abandoned. It could be a nice lightweight alternative to VSCode.
I also think that doc page is a little old. The feature is over 2 years old now and hot reloading is inherently "unsafe" in any compiled language. It's just letting you know that Rust's safety guarantees might go out the window if there are bugs in the code that handles hot-reloading.
The code generation is certainly a build step. This kind of code generation is common for interfaces defined outside of a project's programming language.
KDE Plasma 6 will have some basic support for HDR features when it comes out. The Wayland color management protocol needed for full support is not yet finalized although there is a working informal implementation of HDR for the Steam Deck OLED.