The way MSFS currently works, UNLESS YOU LIMIT FRAMERATE, either your CPU or GPU (or both if the system is “balanced” for your use and settings) will be running at max. Ergo, if you do not want that and you want headroom, the only way to achieve that is to limit FPS. That is of course kinder on the hardware.
And even in that case, I still consider a balanced system to be desirable as you will stress both components equally “lightly” and you will have similar headroom in both. Isn’t that a good thing?
All things approximately of course as the load across the CPU and GPU varies over time on any flight.