what the heck is lift?

I don't follow the point you are trying to make here. The
increased lift does affect the RW. As the glider
accelerates upwards, it begins to match the upward motion of
the air, changing the RW back to the previous RW. I
attribute the upward acceleration mostly to the increased
lift and only partly to the increased drag. You claim that
the vertical component of lift is unchanged.
issued with the Curtis-Wright flyer)

When the motion of an object is caused by lift it will never reduce the
relative airflow that initially caused that motion it will increase the
speed and change the direction of it. This is why wind powered vehicles
can move faster than the wind they are powered by. When the motion of
an object is caused by drag the faster it moves the less drag it
generates because the less relative airflow it generates. It is
impossible for the increased lift to do anything but increase the
relative airflow if that object is allowed to move as a result of it
(lift). If the glider accelerates upward and relative airflow decreases
the only aerodynamic force that can cause that is drag. You claim that
the increased lift does affect the RW but it actually will affect it
the complete opposite way that you say it does if the upward
acceleration were due to lift.

Lets say you are holding a propeller in the wind. The relative airflow
caused by the wind causes the propeller to tend to rotate. If the
propeller were to be allowed to rotate as a result of this lift the
relative airflow now influencing the prop is still all of the wind plus
the relative airflow caused by its motion. The relative airflow is
made up by the actual motion of the air (Wind) plus the motion of the
propeller thru the wind. Objects that move as a result of drag don't
move thru the air they move with the air.