Need to increase a too-quiet audio track above 6dB

I'm a podcaster. I'm using GB 10.3.5. My guest's track is barely audible. I reduced/removed Noise Reduction and got a little bit more volume back, but if possible, I need to boost this track beyond the 6dB max.

I watched a YT video where the host was using an earlier version of GB, and he made it look doable and easy. I installed the AU Peak Limiter on that track, but I don't see how to increase the gain. I'm a novice with GB and I would REALLY like to salvage this track.

thx in advance!