Jetpack compose is created by google as a framework, coroutines and suspend functions are created by JetBrains, as a framework and a language feature . JetBrains can add new concepts and keywords in a language, google can't .

Moreover suspend is a programming language paradigm , signifying that language will support any kind of suspend mechanisms (coroutine being one of them, however this can change in future, that's why even coroutines is also not baked in) . However programming languages are not required to bake in direct support of UI frameworks.