If it’s a stereo shotgun mic, you could try making a version of the audio which only has what is common to both channels
In audacity you can do that using isolate center, (inevitably the result is mono).
If it’s a mono mic, (both tracks absolutely identical) then that technique won’t help.
Then your only hope is an expander to shorten any reverberation below a threshold.
Audacity’s noise reduction can be used as an expander, see … Echo Reduction and Optimizing - #3 by kozikowski