The Linux kernel is an implementation detail.

There is nothing UNIX related exposed to userspace.

Java and Kotlin applications, while NDK APIs are clearly defined,

https://developer.android.com/ndk/guides/stable_apis

Or Treble Project for that matter,

https://source.android.com/devices/architecture/hidl

Try to use private APIs (which is what the Linux underpinnings are) and the application might be blessed with being killed by the OS.