Wish I had better news but on my Linux system, whether or not PNGTuberPlus picks up on the mic correctly seems almost random.
Without rebooting the whole system, I can re-run PNGTuberPlus and sometimes it works normally and sometimes it doesn't.
I found some more logs by running the program through the terminal and adding the `--verbose` option.
But I saw nothing that looked like an error to track down.
EDIT:
Update, it seems even when the program picks up on the mic, it can drop it randomly and go back to not picking up audio.