I just used Spitfish as an example to show de-esser plugins can have an mono-stereo control.
I though the recording was technically good, the most noticeable problem was that the volume of the different people varied too widely, e.g. of the two men speaking one is much louder.
This wide variation in volume can be reduced by “dynamic range compression”: which makes the loud bits quieter and the quiet bits louder. Audacity comes with a compressor, (which is in the “Effect” drop down menu) , but plugins like “Chris‘s compressor ” produce a better result.