How to turn off all power-saving features to be sure everything runs at full speed?

[prolog]

This is what I answered in the other thread:

Librem 5 Wi-Fi performance

I don’t know if there is something special to the L5 in this regard but you could try “powertop” which you can normally use to decrease power consumption. Should be in debian repos I think. You have to switch to the correct tab and there you can toggle power saving settings.