Meanwhile, OS X shares a little code with FreeBSD and was partially derived from it around 30 years ago. And the design philosophy of OS X is roughly the opposite of KDE. This situation has engendered at least half a dozen projects over the years, most of which are never really complete, to make a FreeBSD-first DE/UI that works like Mac. And if it can run Mac applications, so much the better!
Unfortunately, this is really hard. Cocoa is a moving target, and contra Wine, Apple is not as pertinaciously obsessed with backwards compatibility as Microsoft. Even much less ambitious (in my estimation) projects like enlightenment 17 and Wayland have struggled to replace major components of the desktop from the ground up.
The first release of FreeBSD was 30 years ago, OS X a little over 20.
That’s extremely difficult to reimplement, even if you lock compatibility to a particular macOS release.
In my experience with some Linux distros goals alone don't necessarily work out, but the approach with trying to be compatible with actual Mac OS apps is already more notable than an Ubuntu reskin.
I think it’s better when a team actually has designers working for them and comes up with their own real UI standards, (see Pop!_OS). IMO Apple’s UI design isn’t particularly good so it’s not like some holy grail we should copy and paste to Linux.
It may not be perfect, but it’s pretty darn good - as especially visible when comparing to this effort presented here. There’s a lot of detail and polish in MacOS interface design and UX people don’t realise until it’s missing.
Fixed that for you…
However, as someone who has used GUIs from SunView/Irix Desktop/DECwindows to iPadOS/MacOS, via Windows 2.0/3.0/95/NT/etc. I am of the opinion that Apple is still the most consistent and easy to learn GUI. Even my 80-year old mother manages quite well with her Mac and iPhone.
We have decades-old projects like GNOME, KDE and GNUstep and none of them come close to macOS in terms of „finesse“. Despite some of them having corporate backing.
So I just don’t see that happening for a project with a small team working on it in their free time. Far too ambitious, I‘ve seen projects like this fail too often in the last two decades.
Its fascinating to watch their members behave.