void is awesome

If you use a standard package-manager-based taxonomy, there are five base distributions: Slackware, Debian, Red Hat/Fedora/CentOS (I'm unclear on which of those is currently the lowest rung), Arch, and Gentoo. There are also a handful of singletons, like Puppy and Void, which evolved independently (or from long-dead predecessors) but have no family to speak of. I think the only one of those that isn't community-driven is Red Hat.

However, most base distributions are set up because their founder wants to try Something Completely Different, and that "something" is generally not user-friendliness. Even in Debian's case, the core distro philosophy is about software licenses; its user-friendliness is almost a historical accident. Descendant distributions with a premise of "[distro], but user friendly" are not uncommon, though.

Major: Debian, Gentoo, NixOS, Arch and also FreeBSD (not GNU/Linux but still).

Other and esoteric: Void, Alpine, Solus, CRUX, Slackware, Mageia/OpenMandriva,

Corporate sponsored: Fedora, openSUSE

Linux distribution timeline

In my opinion, the only "root distro" which ticks all your boxes is Debian, especially with the advent of Debian 12.

All the other distros are too opinionated to be "user friendly", except maybe Solus which I've never tried.

For all the shit Red Hat has gotten, Fedora Linux is still actually a community base distro.

From what I remember, AOSC OS is fairly easy to install, though it's more niche, so I don't know if I'd recommend it to a new user. There's also Solus, I suppose, but while there is a new release out, I wouldn't count on it remaining actively supported, given its track record. OpenMandriva and Mageia are worth noting, too. Their parent distro was corporate, but it doesn't matter since its dead now. Not a lot else I can think of.

Debian and Void (and Void is iffy. The TTY installer is easy enough though, and it's basically good to go out of the box if you get the glibc iso with Xfce). None of the other base distros are super user-friendly in terms of installation, though I'd add Endeavour OS as an honorary member of the group since it's essentially Arch with a good installer, a friendly community, and nice defaults.

Slackware / opensuse

Solus deserves to be mentioned here, it's a great distro. The project went through some turbulence earlier this year but seems to be back on track as they've just released a new .iso.

Most community distros are small and based on something else; and that's kinda the point. They're not trying to be next big thing, it's just a bunch of people with a common vision that come together to achieve what they need.

Debian and Arch are the exception, and, other than them, the only community distro that isn't based on anything else that I can think of is Mageia.

Edit: OK, I forgot about Solus and Gentoo, but Solus is a zombie at the moment, and op asked for something easy.

OpenSUSE

inb4 but thats a corporate distro, it is just sponsored by SUSE but is community maintained

I agree that there are not many distros that are both user friendly and not forks of something else, but I don't see it as an issue, imo there is nothing wrong with forks.