Peertube

Although it's not considered officially supported, you can absolutely install it on your PC. It's been working great for me. The only hangup was disabling read-only mode for editing the OS and changing the default boot up behavior (start in desktop, not big screen mode). Other than those two things, it's pretty much been plug and play.

1. Very true
2. Wayland still has a lot of problems to iron out, and that's not something that will fly with most people as a Windows replacement.
3. KDE and Gnome are bloated messes that have 29394 ways of doing anything, but not everything, which causes frustration in new migrants. They don't want 12 different apps that each can do 70% of the possible options- they want one app that can do 100% (and isn't terminal). Familiarity with windows is also a plus to them, as a migrant.
4. Again, familiarity is a good thing for a migrant.

You're looking at it from the perspective of 'is this the distro that has things I want' which is, not to be rude, completely useless to the person actually migrating from windows.

1. Not usually a problem for most people, and flatpaks are built into the very slick and reliable GUI store to access newer versions.
2. Legitimate issue for people who need those features, though the Wayland cinnamon session is making good progress.
3. Those are fairly advanced features that most average users won't take advantage of. Cinnamon actually has pretty fantastic widgets/extensions.
4. Having a familiar windows-like interface is an advantage for first time users, making the transition far smoother. Different paradigms can be explored after they are comfortable with Linux.

For people dipping their toes into Linux, mint still has everyone beat. No other distro has such a polished onboarding experience, which already experienced Linux users tend to overlook.

1. The welcome screen perfectly walks new users getting their system set up and usable, in particular it makes the GUI driver installer front and center to avoid Nvidia users trying to install the driver from the Nvidia website.
2. The polish and stability of the updater tool and GUI store are not to be underestimated. KDE's discover is clunky and Gnome's software store is extremely slow in comparison.
3. Every common use case is covered out of the box. There will be no hunting for codecs, filesystem support, firewall, samba, etc, which can be a problem on other other distro like Debian, Fedora, or Opensuse.
4. Maintainence is simple, updates aren't super frequent (important on internet limited areas), guides written for a newbie perspective are plentiful, most commercial software not in the repos will offer a simple .deb installer package.

All of those things are critical to not burning a new user, and so far nothing has approached Mint's mastery of onboarding, IMHO.

I was a long time mint user. And I loved it for a couple of years.

But cinnamon just doesn't really do it for me anymore. I've been using fedora kde for a bit and while it's alright, I had issues with really shitty frame rates in like every game with my nvidia card. I think kubuntu may be my new seeet spot soon.

Although opensuse does seem very interesting too. I should give that a go.

As in you have a fully operational Windows installation that you can boot into, alongside another fully bootable OS?

Because that would be incredibly useful, but I was damned if could work it out.