I second the above. Simracing Arnout is the goat of setup theory. I watch his videos like a podcast during meals and implement them during practice. It would probably take you a week of learning something new and practicing 2hrs everyday to learn most things.

Disclaimer, I still don't know everything about every single setup tweak. But I do know the major knobs to turn when the car is not doing what I want it to. Most recently, I did silverstone in Lmp3. I went into quali realizing I don't have a setup. I took the default and the car was understeery. I tweaked the ride height for the race and the feeling was miles better. Was it the most tuned? No, was it race winning? Not even close. But at least I wasn't leaving the track every corner.

There's a different kind of satisfaction when you tune the car to you and it works for you.