PopOS is not too far off from a DeCanonicalled Ubuntu with extensions. It is little more than the Gnome extensions it contains, and the project could just as easily be just the pop-desktop package. They ship a year old desktop and it is rather unrefined.
Wait a minute. Since when are LXQt and XFCE "Distributions" ?
I don't even know what that vaguely gear-like one in the top tier is, or the one next to the geeko in the second tier are.
(Just as a sidenote, as one of the openSUSE LXQt maintainers, and sometimes LXQt Upstream contributor, if we're providing our own distro somewhere, this is the first I've heard of it.)