i'm making an electronic load. pic related is the basics of it. the DAC will output 0 to 2.5V. worst case scenario is i'll have -25 mV offset from U2A (5 mV max input offset * 5 gain) which means 1.25 mA of current flowing through R1 while my DAC is at 0V. obviously i can't deal with this in software because my DAC can't go any lower than 0V.

i therefore need to trim the offset and i found AN-31 which lists offset trim configurations. https://www.ti.com/lit/an/snla140d/snla140d.pdf

do i do the offset at the differential amplifier (U2A)?
or should it be done at the open loop amplifier (U2B)? if so, how do i do this?