I till now haven't figured out how to setup noise reduction in PipeWire. In Pulse, it was very easy. At the present, I'm using https://github.com/noisetorch/NoiseTorch.
This is one of the use-cases of EasyEffects, and one of the motivations behind my switch to pipewire. Select input or output, switch to the effects tab, and add the noise reduction effect.
(I do like PipeWire)