For what it’s worth, I did get this basically working, although it is kinda hacky, and still not 100% reliable: Raspberry Pi 3 B+ wifi does not work until the service is restarted · Issue #82462 · NixOS/nixpkgs · GitHub
For what it’s worth, I did get this basically working, although it is kinda hacky, and still not 100% reliable: Raspberry Pi 3 B+ wifi does not work until the service is restarted · Issue #82462 · NixOS/nixpkgs · GitHub