Q: WIndow regulator/motor replacement

My rear window regulators (both) are either malfunctioning or broken. The motors are still working because I can hear them and see them trying to move. They can slide down perfectly fine, but struggle and never made it up fully. My question are as follows: This issues is most likely the regulators and not the motor? And if this is the case, can I replace just the regulators instead of the motors as well?

Thank you