How (do i need to?) do i balance cells during discharge?
You don't usually try to balance during discharge, just shut down when the lowest cell gets to the minimum voltage level.

Think about it.  What exactly would you to do "balance" cells on discharge?  On charging you turn on shunts across the cells that have higher voltage than the pack median.  That slows down their charging, allowing the other cells to catch up.

Turning on a shunt during discharge makes no sense.  That would only discharge the high cells to the same level as the low cells.  The pack is still limited by the lowest cell, so you get no extra output energy.

You could, in theory, open the connection to any cell that hits the minimum voltage on discharge, then turn on a bypass around it.  That would suddenly decrease the pack voltage as cells hit the minimum voltage, eventually going to 0 pack voltage when the last cell hits the limit.  Such a thing would be complicated to do and probably of little use to the load.  With cells reasonably matched in the first place, the extra energy available from the pack using this method compared to just shutting down the whole pack when the first cell hits the limit is minimal.