As others have said, set vsync to 1/2 or 1/3 refesh during cruise to dramatically reduce your GPU power consumption. For CPU, you can change the power profile to power saver profile during cruise to save a few watts by it disabling the CPU’s turbo function, but just be careful it doesn’t put your system to sleep when MSFS is in the background as that’s what power saver does by default. You can set sleep time to never for the power saver profile to stop this happening.
I have actually set up hot keys to change MSI afterburner profiles to either 100% or 50% GPU power at the press of a hot key and for power profile I use the PowerPlanSwitcher app downloadable through the MS store to right click and change CPU power profiles quickly. As such, it only takes one hot key press and a right click select CPU power mode to reduce system power consumption by about half during cruise phases of flights.