Well Red Hat did make a go at a supported enterprise desktop distro for a time and, as I wrote, Fedora--which Red Hat supports in a variety of ways for various purposes--is pretty much my default Linux distro.

So I'm not being critical. Yes, Red Hat employees do contribute to projects that are most relevant to the desktop even if doing so is not generally really the focus of their day jobs. And, no, other companies almost certainly haven't done more.

Off the top of my head System76 jumps to mind with their hardware and Pop!_OS.

Canonical. at least they used to, although not a fan of the recent (last ten years) Canonical.

Certainly, Ubuntu used to be friendlier to new would-be Linux desktop users for a variety of reasons. (And we could get into some controversial decisions/directions it's taken but I won't.) I'm sure lots of people still run Ubuntu although Canonical is less prominent these days. My impression is that Canonical was sort of a passion project of Mark Shuttleworth's and they're just a lot lower key at this point.

> Can you name a company which does care about the linux desktop?

To some extent Valve. They have to, since the Steam Deck's desktop experience depends on the "Linux desktop" being a good experience.