Using belts or screw is a trade off.
Belts: Fast, inexpensive, less precise than screws, not much cutting power (if you need that – 3d printers do not)
Screws: Slower, more expensive but a lot of power and much more positional accuracy.
Grbl/grblshield works fine with mixed belt/screw designs, but it does have some limitations. Grbl/grblshield has a single maximum velocity for all 3 axes. If the Z axis can’t move as fast as the X and Y the machine must be limited to the speed of he Z axis.
— Alden