They have accepted bugs from NixOS before (there are nearly a 100 marked as "NixOS Linux" at bugs.kde.org), and I don't see any major reason they would stop. It's true there are many patches for the KDE libraries and Plasma, but realistically most of them are fairly "procedural" changes to adapt to non-FHS layouts, etc.
For reference I count about ~66 patch files among the KDE expression in nixpkgs as of today, including Plasma, all libraries, and related apps. Most of them are in the range of 20 lines long, and they are .patch files, i.e. the actual applied diff is smaller than that. The largest patch is barely 190 lines long and it's for Akonadi, mostly rewriting hardcoded FHS paths throughout the codebase.
I agree there are some quirks with most desktop environments on NixOS in my experience but realistically there's a huge amount of stuff in the ecosystem that plays anywhere from well-to-poorly in such environments, and the Linux desktop stack definitely was not designed at a time where this stuff was common. It is what it is, I guess.
For reference I count about ~66 patch files among the KDE expression in nixpkgs as of today, including Plasma, all libraries, and related apps. Most of them are in the range of 20 lines long, and they are .patch files, i.e. the actual applied diff is smaller than that. The largest patch is barely 190 lines long and it's for Akonadi, mostly rewriting hardcoded FHS paths throughout the codebase.
I agree there are some quirks with most desktop environments on NixOS in my experience but realistically there's a huge amount of stuff in the ecosystem that plays anywhere from well-to-poorly in such environments, and the Linux desktop stack definitely was not designed at a time where this stuff was common. It is what it is, I guess.