I have to disagree here. I find using Cinnamon is very close to using windows.

So is KDE, that's why I recommend it over cinnamon and not gnome.

Everything hardware wise pretty much runs out of the box on all desktops and laptops I have installed it on.

That has (mostly) nothing to do with your desktop environment!

Have been using it for years. The one thing I can’t comment on is hdpi. I never owned a high enough resolution screen to have problems with scaling I guess, although I do have a three monitor setup.

Just because you're familiar with it doesn't mean it's the best choice for beginners. People want HDR, mixed refresh rates, and mixed DPI displays to work properly, they do on KDE, they possibly never will on cinnamon. Just as an example, look at the rate of development on KDE based distros vs cinnamon... cinnamon is entirely outclassed. The KDE team is massive, the cinnamon team is a few people with no real funding. ( if you don't believe me, here are the stats for the last month cinnamon side: https://github.com/linuxmint/cinnamon/pulse/monthly vs https://github.com/KDE/plasma-desktop/pulse although you'll note kde isn't developed on github and that's just a mirror. It's not even close, cinnamon has less monthly than 1/10th of the weekly for kde. The KDE text editor alone outpaces all of cinnamon dramatically, https://github.com/KDE/kate/pulse ) The rate of code output and refinement is not even close. The level of customization you can do with KDE vs cinnamon isn't even comparable. If you run into an issue with cinnamon, you're SOL, whereas KDE can actually worry about your bugs, because they have so many more developers.

That's not even going into the massive disparity in security between the two, KDE uses wayland by default, and as a result is SIGNIFICANTLY more secure, just off the top of my head, here's some problems with cinnamon that will not be resolved anytime soon, that have all already been resolved by this transition KDE-side:

1. Every single app can read your keyboard input without asking
2. Every single app can see what every single other app is doing without asking
3. Apps can fullscreen themselves and go over everything else, because they can control their own window placement to any degree they want, again, without asking.

Immutability might be nice, but I think it’s also personal preference. Windows doesn’t have it so it might be a strange feature to new users coming from Windows.

Windows does have it... actually, it only has it. UAC already prevents you from modifying system files. There's no way to turn it off without mucking about in the console. And it's not a personal preference thing at all, it's objectively superior for a beginner, and anything you can do with a normal distro can still be done with an immutable one assuming you have root access.

Reminder that just because something works for you, doesn't mean it's the best choice for a beginner. Try all the options extensively before you make a suggestion, you might not have made the right choice for everyone just because you have made the right choice for yourself. I make these suggestions after YEARS of extensive testing with many people as my guinea pigs.

I have tried giving people cinnamon, it has gone disasterously, usually due to DPI problems. But I don't think it's a safe recommendation at all, just given the security issues.

In short, i think the only reasonable recommendations for beginners in terms of desktop environments, are KDE or Gnome (if they're mac users and are willing to learn something different), unless their hardware is TERRIBLE and old, in which case they might want lxqt or xfce, maybe.