> Just without open-source drivers for some freakish reason

Because manufacturers buy random parts from other suppliers, who may or may not own the source code, and they often legally simply can’t share forward that code.

Nope, it is a custom Linux kernel with goodies that aren't available upstream like first level support for clang, several Rust modules (no need to argue with anti-Rust kernel folks), all security features turned on, and a micro-kernel like driver subsystem, supporting Java, C++ and Rust.