one way to make this work might be to use a modified electromagnetic propulsion to spin the disk. This would eliminate the need for a motor and therefore the limits any motor might have, although purely theoretical, it would be a better way to get the disk spinning and would allow the entire device to be compacted which would make it an easier to utilize tool because it would be relatively small and still be able to spin the disk at really high speeds. By also using two separate inner an outer pieces for the disk, you can further decrease friction by using a magnetic pole in the center with a magnetic field that would end a little before the second, larger piece joins the first, smaller piece. So the smaller piece would be negatively charged, as would the central pole so that they repel, the larger piece would be positively charged with a field that reaches the outer propulsion system which would also act as the gimbal. This way, the complete lack of contact between the disk and gimbal would allow for even faster speeds and enhanced stability. Again, purely theoretical bc I haven't even gone to HS physics. ¯\_(ツ)_/¯