My sense of smell is basically nonexistent so unless it's really strong, I can't smell it. As for the video, it was basically dumping 150psi into the tank (no regulator on a borrowed compressor), but I think it would have vented at muuuch lower pressure based on how quickly it spit out that paper ball. It had almost no time to build pressure in the tank.
I scoped the filler neck all the way to the rubber connector between the filler and the tank and there's nothing obstructing the filler neck.
All that said, earlier this week I drove it about 200 miles in an afternoon and it took gas at a reasonable rate from a slower pump after that, so I have no idea what's going on. There's a station nearby that's got some higher speed pumps that I'm going to go try early next week when I burn some more fuel out of it to see if it really did "fix itself" somehow. Maybe me sticking high pressure air in the tank knocked a valve loose? No idea, but it's working(ish) so I'll call it a win for now, with fingers crossed.