I am also in KL and new to the city. Unlike you, I have been using public transport for most of my life in many different cities. I prefer to travel this way and don't really like to drive, although I can.

The system in KL is one of the nicest I have used. These many systems are way more extensive and convenient that most other places I have been. I agree the confusion level is high, but I have always found help from someone when I do not know which way to go.

You came to the right city to be a newbie on public transport and I hope you keep riding it. 40 myr on Grab is way too much!