In addition to greasing the roller, I've found the adjustment on the front
window track can have a significant effect on the force required to roll
the window up&down. On the inside of the door the screw in the slotted
hole towards the front adjusts how tightly the window tracks squeeze the
glass. You want the glass held firmly enough that it doesn't tilt around
while rolling up&down but loose enough that it's not a struggle.
Consider loosening that screw and play with the adjustment a little.