Test your microsteps - it's a zero-cost/New Years Day-friendly approach to answer your own question.

Don't mistake microsteps for positional accuracy. As a technology it offers a smoother rotation - helps to reduce resonance, and notionally higher resolution, but resolution isn't the same as accuracy. Test with 5:1 or 4:1, see if that brings you joy.

Note, I'm not convinced that it will - but it's a zero-cost check. The problem is that I don't think it's micro-steps that's causing your issue (essentially you're in the electrical domain with micro-steps - the interface between the computer, the stepper driver and the stepper) - the numbers you're talking about don't feel too near any obvious limits (750mm/min = 12.5mm/sec = 2.5rps x 200 x 8 = 4000 steps/sec = 250us/pulse = should be fine/easy... you shouldn't be losing steps).