OS level includes the core system libraries in the userspace. Of course you can argue no such thing exist in Linux. It is the odd one among all OSes, both major

OS level includes the core system libraries in the userspace. Of course you can argue no such thing exist in Linux. It is the odd one among all OSes, both major and minor, in not providing any stable and well-defined system layer. The lack of unified standards in X11 and especially in Wayland/libinput is a huge source of problems in accessiblity and user experience of traditional Linux environments. Each of those IMEs (ibus, fctx,...) are a major pain to setup and configure correctly. They often don't look "native" to the toolkit of the desktop.