I said baseline versions of Linux. Like as I understand it, Arch is considered to be a fundamental branches of the Linux ecosystem as a whole that's the backbone of a great many distros, and I asked for the defining distinctions specifically of these fundamental branches, not certain distros.
Ah misunderstood your question, ok.
First of this does not include desktop environments (aka the look and feel of the experience, that's not exclusive to a root version) and is a entirely different topic, if you want that info i can tell you as well.
The 3 big ones are debian, red hat and arch, gentoo and openmandriva off the top of my head are also baselines, the main differences between each is the preferred package manager and the speed of updates, i'll go through all 3 of the top ones and a few bits i know about the other 2 for now.
All can use applimage, which is similar to plug and play programs on windows, but there are benefits and disadvanges to applimage.
Debian-Common distros under it are Ubuntu and it's derivatives, Linux Mint and Devuan,has by far the most distros:
Most slow with it's updates, i believe the home of flatpak and uses the most common commands, generally the most stable of the 3 but for most users this mainly means slow kernel updates meaning fixes in gaming and other programs take the longest here, sometimes many months.
Generally speaking you use debian or a derivative if you want to install a linux os to a thinkpad, notebook or grandma's pc as the long term support guarantees no issues at the cost of performance in certain specialized tasks like gaming and business tools.
Ubuntu has it's own file type known as snaps, personally i consider these bloated but they must be mentioned.
Red hat-Common distros under it are fedora, nobara and red hat enterprise, has the least amount of distros:
Fedora updates more often than debian but less than arch, if debian updates every 6 months, fedora updates every 1-3, fedora uses it's own command structure for programs and functionality but like all types can be used to use flatpaks (original linux versions and derivatives can use most file systems, i think arch's AUR might be exclusive but you could probably get it working elsewhere if you wanted, bad idea though), generally speaking the red hat distros are the ones more designed around enterprise and business technologies from my experience, but you also have a few that have extra functions like nobara, which is a gaming distro made by glorious eggroll.
Arch -Common derivatives are Steam OS, Garuda and Endeavor OS, less derivatives than debian but gaining ground due to linux gaming becoming viable and more "normal" users using it:
Arch updates as soon as they become available and seem stable, usually weekly updates, while this does bear a very low risk of bugs, it also guarantees all bleeding edge updates come out immediately, making arch imo the best choice for gaming, arch uses the AUR, Chaotic-AUR (precompiled binaries) and can also install flatpak along side each, the benefits of arch are bleeding edge updates, usually faster gaming performance and versatility of program options (though all programs can be made to work on any linux distro if it has a native version).
Gentoo and openmandriva i don't know a ton about, gentoo is designed for everything to be compiled by the user, which is why this is one of the hardest branches to use, as for open mandriva i know even less, only that it is a successor to mandrake linux, a now no longer supported linux branch and that it offers both bleeding edge and stable update versions.