I might be able to suggest something considering the amount of research into magnetic bearings linear accelerators. hours of YouTube homework I’ve studied, I read Medium scales for torque transfer systems onshore and offshore. It reminds me a lot if the möbius track
Found it interesting you looked at how big you could make one 1GW and a 1km across is truly massive. 10kw definitely achieve able. If using a, U or C channel pre rolled with space for the magnetic to slot neatly into place would reduce the need for bulky extra like aligning wheels. This would allow for the coils to run smoothly through it center. It all so give you the option of where you place fixing and attachments point. There’s no end to how much you could scale. it the inverse of the magnetic fluid idea.
Another thing you might want to take inspiration from is the rings transporter from stargate. If you wish to go the magnetic route. You already part way there with the stack of kite rotors. Which looks like
which is very similar to your design. In the aspect of its core principles. The could even counter rotate due to magnetic clogging. There no end of stacking or nesting that you could do here. the fact that it can even have a aerodynamic profiles helps too. It might be a stretch of the imagination and I wouldn’t know how plausible it would be? but any twisting hole creates a vortices much like a tornado. That just my physical observation of natural processes. I’m not even sure if vortex tethering is a thing? Or even the sort of control suffices you might need? My guess would be similar to the Avro car.
I’d reckon you could build a prototype cheaply enough. If you can get 2mm -5mm thick copper flat bar in Suitable lengths or complete coils. Much like banding on creates. Supporting struts to hold the coils in place. then choose where to put the magnetic parts. Then I think you would be away. Added bonus due to induction. You can have wireless transmission. Much like the wireless chargers. You see out there. But way bigger. It just a suggestion, a totally bonkers suggestion. But 10kw could easily be surpassed this way. If i was to guess a ball park figure of 3m diameter £1000 per rotation component. Most of that cost would be the copper and magnets. you can get 100 ceramic magnets for £30 if my memory serves me right depending supplier. There usually fairly strong magnets. Copper roofing strip is what your looking for and it’s about £70 a coil. Then it is only flat bar bent into a v to form as many supporting struts. As needed. That just the back yard bodgers approach. If you don’t have much money you get to figure out how cheaply you can get things made. Pretty quick. The future is magnetic. And electric. Ps. if you use poly magnetic principles you will get far more energy out of it due to concentrated magnetic field. I hope that this inspires a few idea in AWE.