Canot remove RIGHT channel buzz without losing ALL audio.

Noise reduction is a two step process.
#1 select a portion of the audio which only contains noise , (no voice), then click “Get Noise Profile”.
#2 select the part of the track you want the noise removed from , ( probably all of it ) ,
then apply Noise reduction, ( it will “remember” and use the noise profile you last selected in that Audacity session).

If you mistakenly select the entire track as the noise-profile , noise reduction will just reduce the volume of the entire track.

[ If the buzzing is mains-hum may obtain a better result with de-hum plugins , before using noise-reduction, see … Super 8mm Film Audio Clip - #3 by Trebor ]