Effect Dual Tape Decks, nyquist plugin.

To my mind, this effect is not functional. As a result, instead of sound, there is something unintelligible. Then it’s better to remove it from the list.

Have you ever played two tapes of the same song at the same time* ?
If not then you don’t know what effect that plugin is simulating, and are not in a position to judge.

[ * I have, and IMO that 2004 plugin works as specified Audacity 2.2.1 ]