This is tested on " Intel 11th CPU with intel_pstate driver and an NVIDIA GPU with 535 proprietary driver" ,I don't know if this works the same way on AMD CPUs and GPUs

This guide is for normal users that want things just to work with least amount of headache possible

Understanding both normal system power modes & NVIDIA Prime profiles

lets start with Power modes from settings ,each mode does exactly what it says ,that's it ,NVIDIA Prime profiles also do what they say ,but it only affects the state of the GPU ,not the system .

System Power modes tries to apply a state for the whole system .

NVIDIA prime profiles applies a state only for the driver .

How to :

max power saving

• disable the nvidia card , `sudo prime-select intel , don't worry , the integrated GPU in your CPU will take charge
• enable system power saver mode . -reboot

Balanced

• use Nvidia on-demand prime profile .
• use balanced power mode for the system.
• reboot

Max performance

• use Nivida performance mode profile .
• use performance mode for the system .
• reboot the laptop while it's plugged in the charger
• after reboot , change nvidia powerMizer to auto , let the driver do it's thing .

Notes :

1. you can change system modes without rebooting .
2. you should reboot for nvidia prime profiles to take effects .
3. you can mix system power modes and prime profiles but don't make illogical mixes like system power saving mode while running performance mode on nvidia card , this is not recommended .