If you have any trouble, I have 15 years of linux experience and am willing to do infinite support help on matrix, feel free to ask and I can give you a complete rundown and answer any questions you have about any distro.
I highly recommend going with an immutable distribution, such as bazzite, you'll also probably want KDE like you said, which is the desktop environment
You can think of it this way:
the distribution is a separate app store, which app store you have determines what apps are available (apps are called packages in linux, essentially, so, we call the management of these package management)
Fedora is an app store that prioritizes being quick to release new software versions, but also, being a little bit behind to check for bugs
Arch is an app store that doesn't care about being user-friendly, and wants to ship the most up to date stuff, and expects you to do everything yourself.
Debian is an app store that's super slow and prioritizes not missing ANY bugs at all costs, they'll wait years before they update software.
But note that these app stores have nothing to do with the thing you interact with, which is the desktop environment:
for desktop environments, there's KDE, which is basically just the closest thing to windows, but much more customizable, they give you as many ways to do things as is comfortable
Gnome is like macos, they think there should only be one way to do things, and they want you to do things their way, for the sake of user-friendliness and minimizing surface area for mistakes.
I wouldn't worry about the other desktop environments unless you're experienced.
Now, immutability is extremely important for new users, immutability means that there's a core system that's separate from the things you install, essentially. So, you can't fundamentally break things without trying really hard, as a new user you might uninstall something and it turns out it's important for your desktop to work and you're stuck in a command line. You don't want that. (this famously happened to linus tech tips)
Feel free to ask for more help or message me on matrix for whatever you need.
^^this is a KDE fedora immutable distribution that i highly recommend, there's also fedora kinoite, but I recommend this over it, because there's some patent issues with fedora since they're a US-based company, and as a result twitch.tv and some other things don't work out of the box. Bazzite just fixes that, along with some other things for user friendliness.