It is both, but the pressure one contributes more to lift. You can see this when a wing stalls, the airflow separates from the upper surface and the pressure difference is gone. The angle of a stalled wing still means air is directed downwards, but the overall lift is much smaller.
I heard that it was just the angle of the wings redirecting the air downwards as reaction mass, like how a rocket engine shoots air downwards.
It is both, but the pressure one contributes more to lift. You can see this when a wing stalls, the airflow separates from the upper surface and the pressure difference is gone. The angle of a stalled wing still means air is directed downwards, but the overall lift is much smaller.
At least that is what I’ve been told anyways