I don’t want to deter you from the MPCNC, but depending on your budget and the exact nature of the liquid you might be able to buy one of these CNC glue dispensing machines. I know nothing about them, so I don’t know if they have a fixed glue that can be used with them or not, but it might be another term you could try searching for.
On further searching, here’s a design for a motor actuator for a syringe.