@vlads said there’s not really support for the ARM64 simulator right now, but from the sounds of it, just hasn’t gotten any attention.
On that note, @Siu (who has a library built on top of the plugin), was tinkering with the code recently and sent me along a modified build script. Maybe this is what is missing, and I just overlooked the signifcance at the time. 
I’ll see if I can report back with more info.