All noise suppression models (RNNoise, GTCRN, DeepFilterNet) leak background noise and fail to fully remove it

None of the available noise suppression models fully remove background noise. With each model enabled, noise such as keyboard typing, fan noise, and ambient room sound still leaks through to other participants. The problem is worst with RNNoise, less severe with GTCRN, and mildest (but still present) with DeepFilterNet.

Join a voice channel / start a call. Enable noise suppression Produce background noise (e.g. typing, running a fan, playing background audio at low volume). Listen via another participant or the mic test/loopback. Toggle noise suppression off and compare.