Upstox and Zerodha charge brokerage as per order value or max 20 rupees.
But Zerodha takes you for a ride by levying auto-squareoff charges per pending leg of BO order. I was unaware of this for a long time until I once paid more than 300 rupees in squareoff charges for a single BO order that had multiple open legs. I think now they have increased squareoff charges to 50 rupees per open order.
Squareoff charges are fine but if a broker starts applying flat 20 per executed order regardless of quantity, I would be annoyed too as I sometimes take some “tracking positions” in small quantities.