I redesigned the board to fit my new battery safety requirements. Now both cells will be charged separately, protective diodes are used and the voltage can be measured be the ESP.

Also I rearranged things. The board is now divided into the power supply at the top, motor control in the bottom left, accessories at the bottom right and the ESP in the lower center. The 3.3V and 5V regulators are now in parallel and not cascaded anymore.

Although I did all that, the board size only increases by 70mm2