Making a superconductor is easy. Keeping a superconductor is hard.

Except right now, superconductors only work at very low temperatures, and keeping things at low temps in space requires energy.

this is for applying torque to the spacecraft, not generating thrust. these are just magnetorquers, which have been a thing for a while. the only thing new here is that they use superconducting magnets, which i assume just means they can more efficiently create magnetic fields. its cool but its not really a game changing development, more a refinement on an existing technology. science journalism has to make everything sexy for clicks though...

Is there a limit to the amount of thrust that these superconducting magnets could generate in Earth's magnetic field? I read a hypothesis that the UAPs that have been observed to accelerate without any propellent are using superconductors in this way.

Are we finally going to get flying cars and hover boards?

This does not move anything in orbit at all, it's only for turning. It's better than using cold gas thrusters for turning, but this will not move you to a different point at all.