FP2 back connector and FT311 (FP2 back connector is stuck in host mode)

Do you see any reason why the same with required PCM modules for protection on each battery cell should not have any risk any more ?
Openly spoken I don’t understand why there is still no makers advice how to double FP2 power when everybody could complain about the weak FP2 battery power ? The oftenly recommended power banks are an option but they are not the same as a real extended battery pack. I think it is missing here.