For an AAA style result I would create a custom benchmark and step through different settings until the FPS is below a desired threshold.
Basically you take a 2m run of a cinematic sequence that you benchmarked before or that you know the basic triangle count/information of already.
with that sequence you adjust settings one at a time until you get to the least possible acceptable FPS avarage.
I’m not sure if the system you are referring to is some sort of built in tool that does something similar to this with the preset epic settings or what, however the end goal would probably still be to read out the stat fps value to a variable for comparison.
As far as things to tweak on/off when benchmarking the most drastic difference / benefit is usually anything to do with less triangles on screen and less transparent effects on screen.
Particles can add a lot of overhead for instance so if you are targeting lower end systems you would create a way to just globally disable some particles.
These obviously aren’t “presets” but things you would custom create and place into the custom benchmark.
could be useful to run the same game between mobile and PC, but that’s about it? Usually you just set your game to have a minimum hardware prerequisite for PC and release it “fully loaded” without options to disable much or anything since around 1990. Not that this is a good practice…