Many years ago I wanted to become a good driver/racer. I had the will but I knew that the technical side of racing was beyond me in terms of understanding realistic car behavior etc.
GTR by Simbin was released.. and I never raced anyone, at first I just used it as a tool to improve my skills. Both as a driver and as my own race engineer (because the two are linked).
I drove.. it must have been 1000 laps over the course of a month or so. Changing car setups, learning about what each part of the setup did.. and learning the difference in how it felt.. and that's the big thing.. it's not about numbers on a page but knowing how it feels. Drivers always talk about "the feeling". Roll bars, wing levels, tyre pressures, ride heights, gear ratios.. everything. It was very hard at first, but I always loved the Spa track and over time it became easier.
Even in my first online races, I was quick but still rusty in terms of consistency or racecraft. I had a hard enough time in clear air, let alone with racecraft. All the aids were off obviously. Cockpit view. Over the months my racing improved, in a similar way to how I improved when driving solo and "testing". There became a point at a later time, where I was racing at Laguna Seca in the practice session.. and someone shared their Saleen setup with me and I immediately went 3-4 seconds quicker without changing it. They couldn't believe it.. "you did that with my setup.. WTF???"
After a year or two I was way beyond the level I was in that first month, struggling to learn the basics at Spa, spinning the wheels up so much on exit of corners.. or not pushing hard enough on entry into corners for fear of running wide. And my calfs would cramp up a lot too. It took at least 6 months or a year to get proper control of my pedals in terms of being sensitive with them.. and doing that creates a lot of fatigue in the muscles. Over time, like with any exercise.. they adjust to it.. and a muscle memory becomes a part of your body.
Since then I've raced iRacing briefly, lots of F1 stuff in rFactor.. and some other stuff.. but it's always seemed easier by comparison. Like I can jump into anything and within a week or two it all comes back. I haven't raced in a long time, but it never takes long to get "back into form".
I play guitar and it's very similar in a lot of ways. There is a technical side to it, a physical side to it, a muscle memory side and a steep learning curve. The setup of the guitar/amp etc is very important.. and it's very similar to driving in that you have to learn and know what feels right to you. Without that it'll always be hard to be quick in cars, because it's rare that car setups are locked.. and the more ability you have to customize.. the more ability you have to find your sweet spot and be "in the zone" and to enjoy the "feeling". The more that it's tailored to what you like.. the more comfortable you will be.. and the more you will be able to relax and maximize it. Instead of having to fight it and be frustrated. All of this is the kind of thing, that for me has been a fun adventure and even if you go years without doing it.. you have built a core understanding and experience within yourself.. so you can always return to it and get it back quickly. Sort of like doing weights in the gym.
There is no right way to do these things, everyone has their own way. The right way to hold a guitar pick, the right amp, the right balance for a car.. the right type of car. It's just a matter of exploring and learning what feels right to you. And getting the best out of yourself. You only have to learn these things once.. and then it stays with you for life. Where there is a will there is a way.
Just my experiences.. but maybe it can help you. It's a great feeling to have a developed a skill for something and improve it over time.. and it's something that money can't buy. I'd worry less about the driving guides or what other people do.. and just developing that 'feeling' inside of yourself. You can label what you do like early turn in or late braking.. but it's really not important if you are aware of what you are doing.. only that you've tested the limits and backed off of them a bit (to be more consistant).. and over time you just want to be increasing those limits as you fine tune everything and become more precise and disciplined. It takes years..