Thank you for your reply.
Referring to https://duet3d.dozuki.com/Wiki/Choosing_and_connecting_stepper_motors , as stated above the line you quoted
Therefore, to get maximum torque out of your motors without overheating them, you should choose motors with a current rating no more than 25% higher than the recommended maximum stepper driver current.
It says nothing about harming the drivers when driving steppers with higher recommended currents. I know this from industrial Servo Drives: where you can hook up a larger motor than the drive can handle, it just won't get the max power out of the motor, but nothing gets damaged.
I don't need the maximum torque of this stepper, so I would think that - if the drivers don't get too high peak currents (I'd guess that would have to be handled in the trinamics itself), they should be able to drive 2A through a 3.5A rated stepper?
Are there experiences with the Duet2 on larger steppers at underrated currents?
The reason I would like this to work: I'll be converting an existing 3D printer with a nema 24 driving a rather heavy Y-axis. The nema 24 is chosen more for mechanical -easy installation- than peak performance. All the other axis are driven by Nema17's (dual Z w/ two independant drives). And waiting for the duet3 would be annoying as I already have a duet2 that's currently unused.
As always, alternative solutions do exist. But right now getting it to work like this, seems like the nicest/easiest solution.