Yeah, always something like that. I figured it out. Factory reset again, disconnected and reconnected things, still no sound. Ran test tones, those worked. I was poking through the menus on the Pre screen, and found it. No idea why, but one setting was set to something other than "auto" for inputs or outputs, and that one setting caused it not to work. All good now.
Would have figured that out yesterday except it took about 4.5hrs to put the couch together. They mentioned you have to DIY, but they obviously don't tell you how much work that is. It is straightforward and fairly easy, but not exactly quick. Video not too exciting either lol.