The best UNIX desktops experiences were the ones with vertical integration, where the desktop, vendor tooling and hardware provided a unique experience, instead of yet another UNIX fork.
NeWS, NeXTSTEP, Irix, ...
As for Android and Chrome OS, yeah they might use Linux kernel, which is an implementation detail on Android SDK/NDK official APIs for app developers, and on ChromeOS only exposed via the sandboxed Crostini environment.
Google could switch to another POSIX like kernel and app developers would barely notice, only OEMs and people rooting their devices would.
NeWS, NeXTSTEP, Irix, ...
As for Android and Chrome OS, yeah they might use Linux kernel, which is an implementation detail on Android SDK/NDK official APIs for app developers, and on ChromeOS only exposed via the sandboxed Crostini environment.
Google could switch to another POSIX like kernel and app developers would barely notice, only OEMs and people rooting their devices would.