How can I choose which Audio track to transcribe?

I'm trying to utilise the transcribe feature to identify pauses and mass delete them all to cut down a video efficiently. The video has 2 audio tracks, both with left and right channels. Audio track 1 is just background sound from a game, audio track 2 is my microphone, this is the track I need to transcribe. So my mp4 file has V1, A1 and A2 tracks when I import it.

When I transcribe it transcribes the source mp4 file, which means it transcribes the wrong audio. I need to just transcribe audio track 2 so I can then select all Pauses and delete them.

I have tried Generating Static Transcript which allows me to select the audio track I want, but this does not work for deleting pauses as the delete button is greyed out after select them all, I believe deleting pauses is only possible for Dynamic transcripts for some reason.