Well, I played around very briefly in Logic. I wasn't sure if you were wanting me to stick with just using Audacity or if you were asking how I'd actually do it. So I did the latter. This was a real quick job that I did in like 10 minutes. I could probably make it a lot better, but it's fairly simple of an effect, in my opinion. It obviously won't sound 100% like Kylo Ren without Adam Driver's voice. I used a few male Jaden lines.
I can mess around in Audacity too, but yours is pretty good as well. I think this guy kinda gets it as good as you'll get in Audacity.