I enjoyed the way Plasma 4 looked and use the Oxygen theme on Plasma 5 to experience that on a modern desktop environment. Will this theme make its way into Plasma 6?
The people who created Oxygen would have to update it all to keep it current. I’m not holding my breath. I use Breeze Dark, but if Oxygen could do the things Breeze Dark does, like custom accent colors, I would probably go back to that.
I would also welcome the Oxygen theme on Plasma 6.
Oxygen is already ported (though not installed by default).
I have just tested that it seems to work fine on Neon Unstable and openSuse Krypton if you install the respective packages.
There is also an initiative for creating a new version of Oxygen, called Oxygen²:
Yes, it will load and work, mostly, but it will not quite do everything, because they were not built with the same tools. This is why there is an initiative to create a new version. I would like to see a new version of it.