Ok well, your problem is a little worse than you think because 100Khz won't give you 2000Rpm at the Servo. The encoder on the servo is 2500ppr x 4 (quadrature) so 10,000ppr
So 100Khz will only give 600Rpm (100,000/10,000*60).

So to get Full RPM out of the servo you need to use electronic gearing so watch this video I did because I'm not explaining it all again.!!

You could possibly use the E-gearing to give you what you want and then feed the Servo Encoder output back into UCCNC, thou I've got a feeling UCCNC will only allow a max 1000ppr Encoder to be used.?