Need help upgrading RC Car Battery and Motors

I need help upgrading the battery capacity of my RC car from its current 8.4 volts to a target of 36 volts. I also need advice for swapping the 200 RPM motors to ones with a higher RPM and more torque. Here's what I'm in need of:

• Deliverance of reliable information about the right motor type and battery upgrade for the best enhancement.

Here is a PDF of the car assembly
https://github.com/Freenove/Freenove_4WD_Smart_Car_Kit_for_Raspberry_Pi/blob/master/Tutorial(ordinary_wheels).pdf

The right freelancer will provide guidance for every step in the upgrading process, ensuring maximum performance post-modification.