IMHO, rust is more explicit memory management than manual memory management. You don't have to juggle individual calls to malloc and free, but of course there is the borrow checker and you also have to be explicit about things like taking a reference to something versus cloning it.

Thanks to all that, nobody's yet managed to demonstrate a GUI library that really feels like it belongs (in terms of code architecture, but also look & feel).

I sure don't, C++ is pretty commonly used for this usecase and memory management is at least somewhat less manual in Rust than C++