Among professionals, the general consensus is that they are both involved in 100% of the generation of lift, and if one was lacking nothing would happen.
May well be so, but you must have sounded out a very selective group of professionals to arrive at your 'general consensus'!
Try instead Barnard and Philpott (aerodynamics at ... ah, de Havilland Hatfield!), for example:
"It is often thought that the downwash is entirely responsible for the lift, by the principal of momentum change. This is not so. What is invariably forgotten is that the trailing vortices also produce a large upwash outboard of the wing tips. The upward momentum change thus produced cancels out the downward momentum change of the downwash. If we sandwich a wing between the walls of a wind-tunnel, so that there are no trailing vortices, air particles behind the wing will return roughly to their original height, and yet the lift is greater than when downwash is present."
Or Gibson (aerodynamicist at BAe nee English Electric Warton):
"It cannot be said that the current enthusiasts for the sole application of Newton's laws to explain lift have succeeded in rubbishing circulation theory, because they appear not to know it exists. Their ideas are assertions that have utterly failed to provide any quantitative measures of lift, or to explain the physical basis of lift generation, or to suggest how an aerofoil might be designed. It is these ideas that I referred to as nonsense."
Or Anderson (Curator for the National Air and Space Museum, Professor of Aerospace Engineering and quite possibly the most authoritative researcher into the history of aerodynamics):
"First, let us consider what this author advocates as the most fundamental explanation of lift. It is clear [........] that the two hands of nature that reach out and grab hold of a body moving through a fluid (liquid or gas) are the pressure and shear stress distributions exerted all over the exposed surfaces of the body. The resultant aerodynamic force on the body is the net, integrated effect of the pressure and shear stress distributions on the surface. Because the lift is the component of this resultant force perpendicular to the relative wind and because the pressure on the surface of an aerofoil at reasonable angles of attack acts mainly in the lift direction whereas the shear stress acts mainly in the drag direction, we are comfortable in saying that, for lift, the effect of shear stress is secondary and that lift is mainly due to the imbalance of the pressure distributions over the top and bottom surfaces of the aerofoil."