Powering a NEMA 17 motor | Wattage Vs Voltage
Question
Which PSU to use for microstepping NEMA17 steppers at 3.2V, 1.2A per phase?

Answer
(1) Using A4899 and DM542 microsteppers, you can set max phase current, say 1.2A, for your NEMA17.
(2) So you can use high volt PSU as high as 36V, 2A, for your NEMA17 at 3.2V 1.2A /phase.

References
(1) Driving NEMA steppers using microstepper DM542 ... - EESE 2021apr22
(2) Fake microstepping in A4899 ... stepper-drivers? - EESE 2021apr14
(3) What could be the reasons for a stepper motor stuttering with an A4988 driver? - EESE 2021apr05 [Locked]

Appendices
Appendix A - A4899 driving NMEA stepper schematic