I’m pretty attached (perhaps irrationally) to Arch Linux and KDE Plasma — but they’ve been my main driver for many years now. So, in general, I’d prefer just something that can just be installed as a theme, over installing a new distro (or a new DE) for a new UX.
Even a new DE might be something I’ll install on Arch and try out once in a while, but the thought of switching from a rolling-release distro (Arch, in my case) to a point-release distro (e.g. Ubuntu) just to try out a new desktop UX is a bit too much for me.
It does something very similar to your ask. I use it as a daily driver OS and it works really well and I love the UI.