Just buy VOO

Here's the best reason to just do 100% VOO if you’re a US based investor and just starting out - you are going to compare your portfolio to the S&P 500 and most poor decisions are made when you find you are underperforming. At some point in time, any fund that is not an S&P 500 fund will be underperforming (or FOMO) and you are bound to want to sell it for something else that is doing better. That’s called performance chasing and it’s hard to resist. It means you will sell low and buy high which is exactly the opposite of what you should be doing.

P.S. any S&P 500 fund will do, VOO is just the most popular one for buy and hold investors. You could also do a total US market fund but it will also not track 100% with the S&P 500..