The simple solution potential solution would be to put a guard around your paddle so it pushes towards the chute, but it gets covered as it starts pushing away from the chute. I would think you would want the kick plate right at the end of the auger.
What about instead of a paddle, you put a cam on the end that hits a spring loaded piece of metal to push it, more like a mechanical solenoid or piston. The shape has to be like a perfect cylinder that fits inside something. so it doesn’t get material caught behind it. A piston with a crankshaft might also work. but more work.
You could also use a flat rotating disk with maybe a rubber coating on it, the pressure from the auger should be enough to press material against it and nudge it in the right direction, and you don’t have to worry about it wedging up. It might work better flat on the bottom if it was half covered but that is a lot more linkage. And it would work better if it was running faster then the auger itself. but that would probably require a planetary gear for a vertical version, a horizontal version would be easier since you already need some linkage to turn the motion 90 degrees.