Realized kind of a janky solution that seems to do the trick
If your csound instance is set to run at a sample rate lower than that of your Unity project, you can just have a quick check of the csound instance’s sample rate and the projects and then set the pitch of the AudioSource object. So 10K sample rate csound instance, 44.1K sample rate Unity project, AudioSource pitch set to 0.2268
The instance I was running, differences in performance:
10K sr Unity Project, 10K sr csound, Audio Source Pitch 1.0: peak~2.4% consumption
44.1K sr Unity Project, 10K sr csound, Audio Source Pitch 1.0: peak~9.1% consumption
44.1K sr Unity Project, 10K sr csound, AudioSource Pitch 0.2: Peak~2.4% consumption
So this seems to solve the issue without any complicated solutions. Obviously if there was a way to forcibly set OnAudioFilterRead’s sample rate per AudioSource instance, that would be ideal for long term stability purposes, but this seems to do the trick well enough with current versions of Unity