While debatable, I don't think there's any version of Linux that is strictly "intuitive for a long time Windows user", though it can vary greatly on your experience and understanding of computers. That said, getting into Linux isn't incredibly difficult either.
Can't speak to the other emulators you named, but BizHawk has actually worked on Linux for awhile. It's just that Lua wasn't supported until recently, and even before that, you could run it in a Windows VM (as annoying as that was). Generally speaking, anything that only releases on Windows, will probably still function on Linux via wine.
There are a plethora of Linux distros available. You could spend a lifetime exploring them all hehe. First though I think it's best to understand some basic concepts when choosing distros. Under the hood, most distros are very similar to each other, but have a different set of pre-installed packages (software) and configuration that give it its distinct look and feel. One of the most critical differences will be which package manager the distro uses. The package manager is software that you use to install/update/remove other programs; it's vital to using Linux in any practical capacity. Some of the most common include
apt,
yum, and
pacman.
Within that, the next major difference comes from which package repositories the distro makes use of by default. The package manager uses a list of these repositories to actually find packages for installation. Many distros will often have their own repositories for various packages (and this isn't necessarily a good thing).
The other defining feature is which "desktop environment" the distro uses. This is a collection of packages that (usually) gives you a Windows-like desktop, with windows, a taskbar, maybe some desktop shortcuts, file explorer, etc. Some distros will offer multiple options (Linux Mint is a good example of this). Theoretically, because desktop envs are just a set of packages like any other piece of software, you should be able to swap them out with whatever you want, but sometimes you can run into problems if a distro expects a certain desktop env (like missing or broken functionality).
That all said, I recommend you try out
Kubuntu. It is a "flavor" of Ubuntu, which uses the KDE desktop environment. Ubuntu is one of the most popular distros and package repositories in the Linux ecosystem. Ubuntu normally comes with Ubuntu's own desktop env, but frankly I don't like it, and it's definitely
not like Windows at all. KDE on the other hand, is pretty similar, and extremely customizable. Kubuntu is essentially just Ubuntu, but with KDE installed by default.
I suggest choosing version 23.10. The older "LTS" version is often touted for stability, but you also often get stuck with very out-of-date software.
Also, I would strongly suggest you get a new (decently sized) drive to install Linux onto. A clean drive makes the install process a lot simpler (you don't have to mess with existing partitions).
To actually install it,
this should be a pretty decent guide, just that you'll be using the Kubuntu ISO file instead. The installer may look different, but it should follow the same general flow.
Personally, I go for a more custom approach. I install Ubuntu's "Server" version and choose its "minimal install" option. It gives me a practically empty Ubuntu-based installation that has minimal bloat (though I still have to remove a few annoying packages). From there I'll usually install KDE but it depends on my use-case. This isn't something I'd recommend to someone unfamiliar with Linux though; as it requires some experience using just the terminal to perform tasks.
