I used to "suck" at soldering, until one day I was recommended a Louis Rossmann video by Youtube and decided to watch it. Once I saw how much flux he used, I started to use more flux and as it turns out, that was my problem.
That is my problem with this article. Flux is only superficially in a sentence. So my tip to beginners: Cleaning flux is way easier than struggling to solder with little/no flux.