The get new themes button only shows compatable themes right, it looks good, but I don’t want to mess up KDE 6. My other black theme thread was closed, sorry.
Here you go… 
It’s a global theme for Plasma 6. If you want to install it straight from within your browser, then first install ocs-url from the AUR, and then you can click on the pertinent link at that page.
There was a problem with the search things only showing plasma5 addons.
But after checking again now it seems it is correctly providing plasma6 addons.
At least here on Unstable.