For me it's PeppermintOS.
I started my Linux adventure a few years ago, and haven't owned a Windows PC since.
I currently use Arch on my main rig, and I wanted to install Linux on two old laptops that I found laying around in my house
I then remembered the first distro I ever used, which is PeppermintOS, and I was amazed at the latest updates they released.
They even have a mini ISO now to do a net-install with no bloat, with a Debian or Devuan base.
Sadly, I believe the founder passed away a few years ago, which is why I was really happy to see the continuation of this amazing project.
+1 here. I wanted to write the same. Silverblue/ uBlue in particular has a huge potential.
It already is extremely user friendly, but if someone could develop an even more "noob"-friendly version with a great welcome-starter that shows you how to install stuff, a good looking KDE rice, and sells it as extra-distro with it's own website and iso, then it could easily replace Mint as the #1 best beginner distro!
Heck, Bazzite is most of the way there. With how quickly it's been improving, wouldn't surprise me if it had all that pretty soon.