Hello,
I know this is a long time in the past now, but I stumbled across this post after a rather echo-y recording. I found the "Nice and Clean" filter did a lot of good work for me without turning the voice too "robotic". I actually used the "Automatic Gain Control" in Cleanup then "Nice and Clean" and the speakers voice still sounded, although not great, mostly natural - more like a conversation over a video call than actually being in the same room. But he was easier to understand at least!
Anyway, that's just some advice for anyone else who stumbles over this post!