I’m using pipewire in NixOS unstable and it’s working very well. I know they are working in integrating new pipewire configuration with Nix configuration.
I am just waiting the release of the next NixOS stable version, since the integration in the current stable version (20.09) is still lacking some important features.
I can't switch without SELinux support.
Which features do you have in mind? I use NixOS as well, and I’ve been thinking of switching to PipeWire.