How a sky serpent shaft can scale up?

That’s incuring a compexity penalty.
I don’t yet understand how this would work.
Would it be possible to steer the system so that the shaft is at an angle to the wind direction? Because that could be acchieved relatively easily with a lifter system.

Probably a crackpot idea but throwing it out there anyway: One could have the propellar at an angle to the shaft. This could be acchieved by something like a CV Joint. In contrast to the gif, the green axle would continue and the red part would be like the middle section of a sphere with the propellers attached. Now what is needed is something to keep the propeller at the desired angle. That could be a ring bearing on the propeller hub which connects to something that can be kept stable. Simplest solution would be a weight, but more weight is obviously bad. Maybe an rod running below the rest of the system. Maybe weights.
This mechanism could also be used to put the propellers at an angle sideways to get more swept area, in the ‘tensioned between mountains’ use case. The added complexiy probably makes it not worth it though.
I madea a drawing: superturbine variant