The DVR8825 has a continuous motor drive output current max of 2.5 A. For the A4989, is the continuous motor drive output current some value on the FET's datasheet?
For example, if I use the IRFZ44N, would the maximum continuous motor drive output current be 35 A? The datasheet for that FET: infineon.com/dgdl/…
In summary, the DVR8825 driver does not work. I'm wondering if the A4989 is more robust.
I wouldn't say it's more robust, just that it's a different product. Having 8 external FETs will significantly increase the size of your solution, which sometimes matters. Take front-page numbers (e.g. 35A*!) with a grain of salt.
Could try measuring the current going to the driver board. Something sounds wrong though... the DRV8825 can run a (small 3D printer) stepper all day and night and barely get warm.