High Torque Gearing for Large Robots

I'm trying to understand how gearing works for high torque robots. They often use harmonic drives, which although not backdrivable, can achieve very large reduction ratios. Now, how they trade torque for speed and vice versa is quite confusing. In the motors I have looked at, such as the T-MOTOR V602, torque, RPM and power all increase in unison.

In research papers, the spec sheets for robots often list both the maximum torque that can be achieved with the gear ratio along with its highest RPM. The motor obviously cannot do the same simultaneously as it would require 2Kw+ per joint. The question is how are they able to trade one for another in what seems to be a single harmonic/planetary drive?

Image from robot JAXON3-P (doi : 10.1109/Humanoids43949.2019.9035049)

Quote from SkyeFire

The harmonic drives are generally installed b/c most servo motors are better at generating speed than torque, and because it allows finer position control. Servo motor systems are generally better at controlling their speed than their position, but by having dozens or hundreds of motor rotations equate to a single degree of axis motion, through gear reduction, basically allows you to control position by controlling speed.

Quote from panic mode

but for same motor at same voltage one can get different speed or torque by varying duty cycle for example (DC motors) or frequency (AC motors). but the values are in some range.

to get different range, you need not just motor but also a gearbox.

I am aware of how gearing works in that in results in a torque increase with a rotation speed decrease. I plan to use 10:1 quasi direct planetary gearboxes with helical gearing. This will make it highly backdrivable and enable prioperception. What I don’t get however is how they are able to fine tune for torque versus speed after the gearbox has already been implemented.

Quote from panic mode

Motor can reach some max speed... Or max torque... Or max power. But not all at the same time...!

Thanks for the answer… I suspected this is was the case but I was seriously hoping it wasn’t. From having seen other motors, I knew that Max-Power, Max-Torque and Max-RPM were separate entities but that somehow lightweight drone motors adopted a different behavior. In the case of the drone motors, where they almost always only list Max-Power, is there any calculations that can enable you to find the maximum torque and maximum RPM? Having to manually test each and everyone of them would be expensive and time consuming.