Suggested settings for couture are here … https://forum.audacityteam.org/download/file.php?id=22139
Couture can only reduce room-reverb a little bit, you may need more sound absorbing treatment in the room.
Steve’s de-ess plugin is quick, but you have to dial-in the sibilance frequency from the white-hot areas above 4kHz in spectrogram view, (in your case it’s about 6600Hz).