Linux works. It's only a Kernel.

Android is also a linux distro. To you, it might seem as another OS. So from that point of view, each distro would be a dIfferent OS. So you should judge each distro as such.

So, what people told you Linux is, in fact that Kernel on top of a ton other software.

You can't expect all distros to be the same. Because their purposes are different.