The length of the shaft of torque transfer devices including TRPT does not necessarily lead to an increase in altitude, even with a large lifting kite. In the real world TRPT and other torque transfer devices fly at very low altitude, except for the lifting kite. In addition to the horizontal thrust of the rotor(s) (see the video at 1:20 and 2:15), it is due to the catenary sag effect that increases the curvature by multiplying the mass (more in the middle) when the shaft or TRPT length increases (and also the mass by scaling up). As an example the shaft of the torque transfer device (not a TRPT) on the video at 11:15 is very long, but the average altitude remains low, in spite of helium balloons.
See also the right analysis from Dave Santos:Type 1 Lever Principle applies to internal forces of a curved rotating shaft, and the parasitic work required to bend and unbend the rotating catenary curve with each rotation. This drawback increases with shaft or TRPT length, all other things being equal.