Thanks for mentioning this. Bogleheads Wiki [1] is a goldmine of index investing and asset allocation insights for every stage of an individual investor's lifecycle. Highly recommended.
That’s a great low risk way to proceed, but is lazy in my opinion.
For one, those stocks include weapons manufacturers and other poisonous companies that maybe you wouldn’t want to support.
Second, it detached you from your underlying investment. In my opinion the ability to evaluate businesses is itself worth investing in.
Go pick a sector you are interested in. Compile a list of small - mid cap companies (I.e. companies worth hundreds of millions to a few billions). Read up as much as you can on them. What’s their business model? Who leads them? What’s their current state? Invest in the ones that stand out!
Not many people will tell you this because “investing in the index fund will give you amazing returns after 30 years and Warren Buffet said some!!”.
[1] https://www.bogleheads.org/wiki/Main_Page