Init system used to be a big point of deleniation, but I think systemd is the standard now (for better or worse)
The filesystem and networking stack still have some variability.
There's still default applications, kernel modules, a gui app installer, the desktop, included drivers, and many more things that go into a distro. If you go with a distro that uses KDE and you switch to GNOME for example, you might lose a lot of GUI support for customization, might have to build addon packages yourself, etc.
It's all open source at the end of the day, but that optionality leads to a less streamlined user experience and lack of guardrails as soon as you step off the beaten path, than you would get with something like OSX
The package manager is part of it, sure.
The filesystmem is another big part of it (though it's possible most are following XDG now https://specifications.freedesktop.org/basedir-spec/basedir-... )
Init system used to be a big point of deleniation, but I think systemd is the standard now (for better or worse)
The filesystem and networking stack still have some variability.
There's still default applications, kernel modules, a gui app installer, the desktop, included drivers, and many more things that go into a distro. If you go with a distro that uses KDE and you switch to GNOME for example, you might lose a lot of GUI support for customization, might have to build addon packages yourself, etc.
It's all open source at the end of the day, but that optionality leads to a less streamlined user experience and lack of guardrails as soon as you step off the beaten path, than you would get with something like OSX