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There's an app for Android called SoundAbout, which can reroute audio. Not sure how it works, but maybe something similar is possible for Krisp? https://play.google.com/store/apps/details?id=com.woodslink....

This looks intriguing. Do you know if it receives the audio and re-routes or simply changes the routing configuration?

It simply changes the audio configuration. There's no way to intercept and modify audio data on Android, unless you're rooted. :(