In general we bypass the bms for discharge. The bms is used for charging only in most diy boards. Discharge via BMS or Bypass BMS? [SRO]
Max motor amps are different from max battery amps. They are independently configured in your vesc based esc (stormcore). Battery amps occur at your batteries voltage. Motor amps occur at or below your batteries voltage (determined by your motors current rpm). It’s more complicated than that, but in general that’s why you can have higher motor amps than battery amps.