The diversification, for me at least, comes with my ETFs and Unit Trusts. The vast majority of my investments are in funds like this to such a point where the Steinhoff mess didn't affect me that much at all.
This portfolio is for shares that are "safe" and will show growth over the next 12 months. Ideally, I do not want to pick a company, take a chance and if it doesn't work out having to replace it come June with some other "next best thing". A speculative portfolio might be on the cards but I already have cryptos which are volatile AF so I have no appetite to have that kind of risk in a share portfolio at the moment