Practical way of learning System Design?

At FANG and pretty much any tech companies, they like to ask system design questions. I have been preparing for them, but I am a little overwhelmed by the lack of good resources. So far I have used re

At FANG and pretty much any tech companies, they like to ask system design questions. I have been preparing for them, but I am a little overwhelmed by the lack of good resources. So far I have used resources such as Grokking the System Design Interview, system design primer, college textbooks, etc. However, what I found is that these resources often only discuss everything in conception, there are often no actual implementation of the system discussed, which make it confusing to understand in depth. Like for example, a lot of the example would give system interface for API, it often just show the method signatures, but none of the actual detail implementation itself, tools such as load-balancer and zookeeper are mentioned a lot, but there is no concrete example of how any of this is configured. etc. I'm wondering if there are any education resources or course where the instructor actually implement some of the famous system design questions where not only it show you how these system are design conceptually, but also show you the actual implementation of it with source code and everything shown to you, where you actually build these systems discussed.